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Contents Wiring diagrams Section: Exterior Lights All sections

Lighting System Cadillac CTS II

Exterior Lights 54 illustrations ~40942 words

Fastener Tightening Specifications

ApplicationSpecification
MetricEnglish
Front Fog Lamp to Front Fascia Bracket2 N.m18 lb in
Headlamp Capsule Bolt6 N.m53 lb in
Headlamp Capsule Nut6 N.m53 lb in
Headlamp Leveling Sensor Clinch Nut - Front9 N.m80 lb in
Headlamp Leveling Sensor Clinch Nut - Rear9 N.m80 lb in
High Mount Stop Lamp to the Rear Compartment Lid Nut4 N.m35 lb in
High Mount Stop Lamp to Liftgate Upper Applique Screw-Wagon2.5 N.m22 lb in
Overhead Console Reading Lamp Screw2.0 N.m18 lb in
Quarter Panel Upper Rear Liftgate Opening Molding Screw1.5 N.m13 lb in
Rear Fog Lamp Bracket to Lamp Assembly Screw - European1.5 N.m13 lb in
Tail Lamp to the Body Panel Nut6 N.m53 lb in
Tail Lamp to the Body Panel Nut-Wagon6 N.m53 lb in

Scheme 1

Scheme 1: Headlights/Daytime Running Lights (DRL) Schematics
Scheme 1: Headlights/Daytime Running Lights (DRL) Schematics

Scheme 2

Scheme 2
Scheme 2

Scheme 3

Scheme 3
Scheme 3

Scheme 4

Scheme 4
Scheme 4

Scheme 5

Scheme 5
Scheme 5

Scheme 6

Scheme 6
Scheme 6

Scheme 7

Scheme 7
Scheme 7

Scheme 8

Scheme 8: Fog Lights Schematics
Scheme 8: Fog Lights Schematics

Scheme 9

Scheme 9
Scheme 9

Scheme 10

Scheme 10: Exterior Lights Schematics
Scheme 10: Exterior Lights Schematics

Scheme 11

Scheme 11
Scheme 11

Scheme 12

Scheme 12
Scheme 12

Scheme 13

Scheme 13
Scheme 13

Scheme 14

Scheme 14
Scheme 14

Scheme 15

Scheme 15
Scheme 15

Scheme 16

Scheme 16
Scheme 16

Scheme 17

Scheme 17: Interior Lights Schematics
Scheme 17: Interior Lights Schematics

Scheme 18

Scheme 18
Scheme 18

Scheme 19

Scheme 19: Interior Lights Dimming Schematics
Scheme 19: Interior Lights Dimming Schematics

Scheme 20

Scheme 20
Scheme 20

Scheme 21

Scheme 21
Scheme 21

DIAGNOSTIC CODE INDEX

DTCDescription
DTC B1010B1010 52: System Sensors Data Mismatch
DTC B1395B1395 03: Device Voltage Reference Output 1 Circuit Voltage Below Threshold B1395 07: Device Voltage Reference Output 1 Circuit Voltage Above Threshold
DTC B1461 or B1462B1461 00: Left Headlamp Horizontal Motor Circuit No Additional Information B1461 02: Left Headlamp Horizontal Motor Circuit Short to Ground B1461 39: Left Headlamp Horizontal Motor Circuit Internal Electronic Failure B1461 54: Left Headlamp Horizontal Motor Circuit Temperature High B1462 00: Right Headlamp Horizontal Motor Circuit No Additional Information B1462 02: Right Headlamp Horizontal Motor Circuit Short to Ground B1462 39: Right Headlamp Horizontal Motor Circuit Internal Electronic Failure B1462 54: Right Headlamp Horizontal Motor Circuit Temperature High
DTC B2530B2530 00: Front Fog Lamps Control Circuit
DTC B2545B2545 00: Backup Lamps Circuit
DTC B2555B2555 01: Passenger Compartment Lamp Control Circuit Short to Battery B2555 02: Passenger Compartment Lamp Control Circuit Short to Ground
DTC B2575B2575 00: Headlamp Low Beam Control Circuit
DTC B257AB257A 00: Headlamp Switch Input Signals Mismatch
DTC B2580B2580 00: Headlamp High Beam Control Circuit
DTC B2585B2585 00: Park Lamp Control Circuit
DTC B2600B2600 00: Daytime Running Lamp Control Circuit
DTC B2610B2610 00: Passenger Compartment Dimming 1 Circuit
DTC B2615B2615 00: Passenger Compartment Dimming 2 Circuit
DTC B261AB261A 00: Passenger Compartment Dimming 4 Circuit Short to Ground
DTC B2625B2625 00: Passenger Compartment Dimming Request Signal Circuit Voltage Below Threshold
DTC B2645B2645 03: Ambient Light Sensor Circuit Voltage Below Threshold B2645 07: Ambient Light Sensor Circuit Voltage Above Threshold
DTC B2652B2652 00: Passenger Compartment Dimming 3 Circuit
DTC B3410 or B3420B3410 01: AHLD Front Axle Sensor Signal Circuit Short to Battery B3410 02: AHLD Front Axle Sensor Signal Circuit Short to Ground B3410 03: AHLD Front Axle Sensor Signal Circuit Voltage Below Threshold B3410 07: AHLD Front Axle Sensor Signal Circuit Voltage Above Threshold B3420 01: AHLD Rear Axle Sensor Signal Circuit Short to Battery B3420 02: AHLD Rear Axle Sensor Signal Circuit Short to Ground B3420 03: AHLD Rear Axle Sensor Signal Circuit Voltage Below Threshold B3420 07: AHLD Rear Axle Sensor Signal Circuit Voltage Above Threshold
DTC B3435 or B3440 (V-Series)B3435 00: AHLD Left Servo Driver Circuit B3435 02: AHLD Left Servo Driver Circuit Short to Ground B3435 39: AHLD Left Servo Driver Circuit Internal Electronic Failure B3435 54: AHLD Left Servo Driver Circuit Over Temperature B3440 00: AHLD Right Servo Driver Circuit B3440 02: AHLD Right Servo Driver Circuit Short to Ground B3440 39: AHLD Right Servo Driver Circuit Internal Electronic Failure B3440 54: AHLD Right Servo Driver Circuit Over Temperature
DTC B3435 or B3440 (Base)B3435 00: AHLD Left Servo Driver Circuit B3435 02: AHLD Left Servo Driver Circuit Short to Ground B3435 39: AHLD Left Servo Driver Circuit Internal Electronic Failure B3435 54: AHLD Left Servo Driver Circuit Over Temperature B3440 00: AHLD Right Servo Driver Circuit B3440 02: AHLD Right Servo Driver Circuit Short to Ground B3440 39: AHLD Right Servo Driver Circuit Internal Electronic Failure B3440 54: AHLD Right Servo Driver Circuit Over Temperature
DTC B3445 or B3884B3445 00: Stop Lamp Circuit B3884 00: Center High Mounted Stop Lamp (CHMSL) Circuit
DTC B3588B3588 02: Rear Fog Lamp Switch Circuit Short to Ground
DTC B3600B3600 03: Passenger Compartment Dimming Request Signal Circuit Voltage Below Threshold
DTC C0277 or C0890C0277 06: Brake Pedal Position Sensor Circuit Short to Ground or Open C0277 07: Brake Pedal Position Sensor Circuit Voltage Above Threshold C0277 09: Brake Pedal Position Sensor Circuit Rate of Change Above Threshold C0277 4B: Brake Pedal Position Sensor Calibration Not Learned C0890 03: Device Voltage Reference Output 3 Circuit Voltage Below Threshold C0890 07: Device Voltage Reference Output 3 Circuit Voltage Above Threshold
DTC C0297C0297 00: Brake Applied Output Circuit

DIAGNOSTIC CODE INDEX

Diagnostic Instructions

  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

Diagnostic Fault Information

CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Headlamp Leveling Sensor 5 Volt Reference - FrontB3410 02, 1B3410 02, 1B3410 01, 1
Headlamp Leveling Sensor 5 Volt Reference - RearB3420 02, 1B3420 02, 1B3420 01, 1
Headlamp Leveling Sensor Signal - FrontB3410 03, 1B3410 03, 1B3410 07, 1B1010 52
Headlamp Leveling Sensor Signal - RearB3420 03, 1B3420 03, 1B3420 07, 1B1010 52
Headlamp Leveling Motor Control Circuit 1 - LeftB3435 02B3435 00B3435 00B3435 39, B3435 54
Headlamp Leveling Motor Control Circuit 2 - LeftB3435 02B3435 00B3435 00B3435 39, B3435 54
Headlamp Leveling Motor Control Circuit 3 - LeftB3435 02B3435 00B3435 00B3435 39, B3435 54
Headlamp Leveling Motor Control Circuit 4 - LeftB3435 02B3435 00B3435 00B3435 39, B3435 54
Headlamp Leveling Motor Control Circuit 1 - RightB3440 02B3440 00B3440 00B3440 39, B3440 54
Headlamp Leveling Motor Control Circuit 2 - RightB3440 02B3440 00B3440 00B3440 39, B3440 54
Headlamp Leveling Motor Control Circuit 3 - RightB3440 02B3440 00B3440 00B3440 39, B3440 54
Headlamp Leveling Motor Control Circuit 4 - RightB3440 02B3440 00B3440 00B3440 39, B3440 54
Headlamp Leveling Sensor Low Reference - Front1
Headlamp Leveling Sensor Low Reference - Rear1
1. Headlamp Leveling Malfunction

Circuit/System Description

The front and rear suspension position sensors provide the headlamp control module with front and rear suspension position information. Each sensor receives a 5 V reference, signal, and low reference circuits from the headlamp control module. The sensor are connected to the control arms at the front and rear suspension. As the vehicle travels, the suspension compresses and rebounds moving the suspension position sensor arms. This causes the signal output of the sensors to change. The headlamp control module compares the information from the front and rear suspension position sensors and adjusts the headlamp leveling as needed.

Conditions for Running the DTC

  1. Battery voltage must be between 9-16 V.
  2. Ignition ON.
  3. Headlamps ON.

Conditions for Setting the DTC

The headlamp control module detects a pitch angle that is physically unachievable by the vehicle for 3 consecutive monitoring cycles.

Action Taken When the DTC Sets

When DTC B1010 52 sets as current, the following actions are taken

  1. If the headlamp leveling actuators have positioned the headlamps above the nominal level, the headlamp level controller will drive the headlamps to the nominal setting.
  2. If the headlamp leveling actuators have positioned the headlamps below the nominal level, the headlamp level controller will disable the headlamp leveling actuators and maintain the lower than nominal level.

Conditions for Clearing the DTC

  1. The condition responsible for setting the DTC no longer exists.
  2. A history DTC will clear once 50 consecutive malfunction free ignition cycles have occurred.

Diagnostic Aids

Note. The headlamp control module is not capable of detecting an actual mechanical failure of the suspension position sensors. When the headlamp control module determines that the vehicle pitch angle is physically impossible, the headlamp control module will assume that a mechanical failure has occurred to one of the suspension position sensors.

Reference Information

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Testing

  1. Ignition OFF, disconnect the front headlamp leveling sensor arm from the ball and socket.
  2. Ignition ON, headlamps ON, observe the appropriate scan tool Headlamp Control Module Motor Position Status parameter while moving the front headlamp leveling sensor arm up and down. The reading should change as the arm is moved. If the reading does not change, replace the front headlamp leveling sensor.
  3. Connect the front headlamp leveling sensor arm to the ball and socket.
  4. Ignition OFF, disconnect the rear headlamp leveling sensor arm from the ball and socket.
  5. Ignition ON, headlamps ON, observe the appropriate scan tool Headlamp Control Module Motor Position Status parameter while moving the rear headlamp leveling sensor arm up and down. The reading should change as the arm is moved. If the reading does not change, replace the rear headlamp leveling sensor.
  6. If all circuits test normal, replace the headlamp control module.

Repair Procedures

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Headlamp Leveling Front Suspension Height Sensor Replacement»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system)
  2. «Headlamp Leveling Rear Suspension Height Sensor Replacement»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system)
  3. «Control Module References»(/cadillac/cts/ii-2007-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for headlamp control module replacement, setup, and programming
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of the diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Body Control Module (BCM) 1 Fuse B+B1395 03B1395 03
Body Control Module (BCM) 7 Fuse B+B2652 00B2652 00
I/P Dimmer Switch B+ Voltage ReferenceB1395 031B1395 07
I/P Dimmer Switch SignalB1395 0311
I/P Lamps Dimmer Switch SignalB2652 0011
Indicator Dimming ControlB2625 0011
LED Backlight Dimming ControlB2610 0011
I/P Dimmer Switch Ground1
1. Interior Backlighting Malfunction

The instrument panel (I/P) lamp dimmer switch is used to increase and decrease the brightness of the interior backlighting components. The I/P dimmer switch provides a voltage signal that will increase as the brightness of the lights are increased and decrease as the brightness of the lights are decreased. The body control module (BCM) provides a low reference signal and a B+ voltage reference to the I/P dimmer switch. When the I/P dimmer switch is placed in the desired position, the dimmed voltage setting is applied from the I/P dimmer switch through the I/P dimmer switch signal circuit to the BCM. The BCM interprets the signal and applies the dimmed voltage to the I/P lamps supply voltage circuit and the interior backlighting components dim to the requested level.

Battery voltage must be between 9-16 V.

B1395 03

The DTC will set for the following conditions

  1. The BCM detects a short to ground in the I/P dimmer switch voltage reference circuit.
  2. The BCM detects a short to ground in the I/P dimmer switch signal circuit.
  3. The BCM detects a short to ground or an open/high resistance in the BCM 1 fuse B+ circuit.

B1395 07

The BCM detects a short to voltage in the I/P dimming voltage reference circuit or the vehicles system voltage exceeds the normal operating range of 16 V.

Actions Taken When the DTC Sets

  1. The I/P dimmer switch will not operate.
  2. The I/P dimming lamps will not illuminate.
  1. The condition responsible for setting the DTC no longer exists.
  2. A history DTC will clear once 100 consecutive malfunction-free ignition cycles have occurred.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

Ignition ON, cover the ambient light sensor, vary the interior lamp dimming switch from dim to full bright. The lamps should dim and then become full bright.

  1. Ignition OFF, disconnect the harness connector at the I/P Dimmer switch.
  2. Ignition OFF, verify that a test lamp illuminates between B+ and the ground circuit terminal 10. If the test lamp does not illuminate, test the ground circuit for an open/high resistance.
  3. Ignition ON, test for B+ between the voltage reference circuit terminal 5 and ground. If less than the specified value, test the voltage reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM.
  4. Install a 3 A fused jumper wire between the signal circuit terminal 9 and the voltage reference circuit terminal 5. Verify the scan tool Dimming Control Signal parameter is greater than 2.5 V. If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM.
  5. If all circuits test normal, replace the I/P dimmer switch.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Instrument Panel Lamp Dimmer Switch Replacement»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system)
  2. «Control Module References»(/cadillac/cts/ii-2007-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM replacement, setup, and programming
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
AFL Headlamp Motor Control Circuit 1 - LeftB1461 02, 1B1461 00, 1B1461 00, 1B1461 39, B1461 54
AFL Headlamp Motor Control Circuit 2 - LeftB1461 02, 1B1461 00, 1B1461 00, 1B1461 39, B1461 54
AFL Headlamp Motor Control Circuit 3 - LeftB1461 02, 1B1461 00, 1B1461 00, 1B1461 39, B1461 54
AFL Headlamp Motor Control Circuit 4 - LeftB1461 02, 1B1461 00, 1B1461 00, 1B1461 39, B1461 54
AFL Headlamp Motor Control Circuit 1 - RightB1462 02, 1B1462 00, 1B1462 00, 1B1462 39, B1462 54
AFL Headlamp Motor Control Circuit 2 - RightB1462 02, 1B1462 00, 1B1462 00, 1B1462 39, B1462 54
AFL Headlamp Motor Control Circuit 3 - RightB1462 02, 1B1462 00, 1B1462 00, 1B1462 39, B1462 54
AFL Headlamp Motor Control Circuit 4 - RightB1462 02, 1B1462 00, 1B1462 00, 1B1462 39, B1462 54
1. Adaptive Forward Lighting Malfunction

Battery positive voltage is applied to the headlamp control module at all times. The headlamp control module has a normal operational voltage range of about 12.5-16 V and is only fully functional with the ignition switch is in the RUN position and the headlamp switch in the AUTO position. The communications enable signal from the BCM wakes the headlamp control module microprocessor. The headlamp control module receives serial data messages from the engine control module (ECM), transmission control module (TCM), electronic brake control module (EBCM), and body control module (BCM) with regards to power mode, speed, steering angle, transmission gear selection, and headlamp switch status. The headlamp control module calculates the headlamp angle and sends commands to the left and right adaptive forward lighting system (AFL) headlamp actuators. The headlamp actuators drive the headlamps to the position commanded by the headlamp control module. The headlamp control module monitors the headlamp actuator motor control circuits for proper circuit continuity and for shorts to ground or voltage. If a malfunction is detected, a DTC will be stored in memory and the driver will be notified with a message displayed over the driver information center (DIC) located on the instrument panel cluster (IPC).

  1. Battery voltage must be between 9-16 V.
  2. Ignition is in the RUN or ON position.
  3. Headlamp switch is in the AUTO position.
  4. High or low beam headlamps must be active.
  5. Vehicle speed greater than 2 mph.
  6. Transmission is in the DRIVE position.

DTC B1461 00

The headlamp control module detects a short to voltage or an open/high resistance on any of the left headlamp actuator control circuits.

DTC B1461 02

The headlamp control module detects a short to ground on any of the left headlamp actuator control circuits.

DTC B1461 39

The headlamp control module detects an internal electronic failure.

DTC B1461 54

The headlamp control module detects an overheating condition on any of the left headlamp actuator control circuits.

DTC B1462 00

The headlamp control module detects a short to voltage or an open/high resistance on any of the right headlamp actuator control circuits.

DTC B1462 02

The headlamp control module detects a short to ground on any of the right headlamp actuator control circuits.

DTC B1462 39

The headlamp control module detects an internal electronic failure.

DTC B1462 54

The headlamp control module detects an overheating condition on any of the right headlamp actuator control circuits.

  1. When DTC B1461 or DTC B1462 sets, the headlamp control module will attempt to return the lamps to a nominal position and disable all requests to both headlamp actuators.
  2. The driver information center (DIC) will display AFL Lamps Need Service.
  3. On vehicles equipped with both AFL and headlamp leveling, the headlamp leveling system will be disabled.
  1. The condition responsible for setting the DTC no longer exists and the ignition is cycled.
  2. A history DTC will clear once 50 consecutive malfunction-free cycles have occurred.

Diagnose any faults to the vehicle stability enhancement system (VSES) which contains the steering wheel position sensor before proceeding with this diagnostic procedure. A fault within the steering wheel position sensor will cause the adaptive forward lighting system to be inoperative.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

Ignition ON, with a scan tool, command the AFL Motor Control left and right while observing both headlamps. The headlamps should turn to the left and right positions as commanded.

  1. Ignition OFF, disconnect the harness connector at the appropriate headlamp.
  2. Remove the AFS 15A fuse.
  3. Ignition OFF, scan tool OFF, test for 10 ohms-25k ohms between the control circuit terminals listed below and ground: AFL motor control terminal 1 AFL motor control terminal 2 AFL motor control terminal 3 AFL motor control terminal 4 If greater than the specified range, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the headlamp control module. If less than the specified range, test the control circuit for a short to ground. If the circuit tests normal, replace the headlamp control module.
  4. Install the AFS 15A fuse.
  5. Ignition ON, scan tool OFF, headlamps ON, verify that a test lamp does not illuminate between the control circuit terminals listed below and ground: AFL motor control terminal 1 AFL motor control terminal 2 AFL motor control terminal 3 AFL motor control terminal 4 If the test lamp illuminates, test the control circuit for a short to voltage. If the circuit tests normal, replace the headlamp control module.
  6. If all circuits test normal, replace the appropriate headlamp assembly.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Headlamp Assembly or Headlamp Bulb and/or Cornering, Sidemarker, Park, Turn Signal Bulb Replacement (TT6)»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system) or «Headlamp Assembly or Headlamp Bulb and/or Cornering, Sidemarker, Park, Turn Signal Bulb Replacement (TT7)»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system) or «Headlamp Assembly or Headlamp Bulb and/or Cornering, Sidemarker, Park, Turn Signal Bulb Replacement (TT8)»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system__headlamp-assembly-or-headlamp-bulb-andor) or «Headlamp Assembly or Headlamp Bulb and/or Cornering, Sidemarker, Park, Turn Signal Bulb Replacement (Without TT6/TT7/TT8/T84/T85)»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system)
  2. «Control Module References»(/cadillac/cts/ii-2007-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for headlamp control module replacement, setup, and programming
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Front Fog Lamp Switch Signal222
Front Fog Lamp Relay Control11B2530 00
Front Fog Lamp Control111
Fog Lamp - LF Ground1
Fog Lamp - RF Ground1
Fog Lamp Switch Ground2
1. Front Fog Lamps Malfunction 2. Front Fog Lamp Switch Malfunction

The front fog lamp relay is supplied with battery voltage at all times. The front fog lamp switch signal circuit is grounded momentarily by pressing the front fog lamp switch. The body control module (BCM) energizes the front fog lamp relay by applying ground to the front fog lamp relay control circuit. When the front fog lamp relay is energized, the relay switch contacts close and battery voltage is applied through the FRT FOG fuse to the front fog lamp supply voltage circuit which illuminates the front fog lamps.

  1. Battery voltage must be between 9-16 V.
  2. Front fog lamps ON.

The BCM detects a short to voltage in the front fog lamp relay control circuit for 5 seconds or greater.

The front fog lamps will not operate when the park lamps are ON and the front fog lamp switch is active.

  1. The condition responsible for setting the DTC no longer exists.
  2. A history DTC will clear once 100 consecutive malfunction-free ignition cycles have occurred.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition OFF, disconnect the front fog lamp relay.
  2. Connect a test lamp between the B+ circuit terminal 85 and the control circuit terminal 86.
  3. Command the Fog Lamps ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states. If the test lamp is always ON, test the control circuit for a short to ground. If the circuit tests normal, replace the BCM. If the test lamp is always OFF, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the BCM.
  4. If all circuits test normal, replace the front fog lamp relay.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Relay Replacement (Attached to Wire Harness)»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-repair-instructions) or «Relay Replacement (Within an Electrical Center)»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-repair-instructions)
  2. «Underhood Electrical Center or Junction Block Replacement»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-repair-instructions)
  3. «Control Module References»(/cadillac/cts/ii-2007-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM replacement, setup, and programming
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Body Control Module (BCM) 4 Fuse B+B2545 00B2545 00
Backup Lamps ControlB2545 0011
Backup Lamp - Left Ground1
Backup Lamp - Right Ground1
1. Backup Lamps Malfunction

When the transmission is placed in the REVERSE position, the transmission control module (TCM) sends a serial data message to the body control module (BCM). The message indicates that the gear selector is in the REVERSE position. The BCM applies battery voltage to the backup lamps and inside rearview mirror. Once the driver moves the gear selector out of the REVERSE position, a message is sent by the TCM via serial data requesting the BCM to remove battery voltage from the backup lamp control circuit. The engine may need to be running for the backup lamps to function.

Battery voltage must be between 9-16 V.

DTC B2545 00 will set when one of the following conditions exists

  1. The BCM detects a short to ground in the backup lamps control circuit.
  2. The BCM detects a short to ground or an open/high resistance in the BCM 4 fuse B+ circuit.

The backup lamps will not operate.

  1. The condition responsible for setting the DTC no longer exists.
  2. A history DTC will clear once 100 consecutive malfunction-free ignition cycles have occurred.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition OFF, disconnect the harness connector at the inside rearview mirror.
  2. Connect a test lamp between the control circuit terminal 9 and ground.
  3. Command the Backup Lamps ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states. If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the BCM. If the test lamp is always OFF, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, test the BCM 4 fuse B+ circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM.
  4. Connect the harness connector at the inside rearview mirror.
  5. Ignition OFF, disconnect the harness connector at the appropriate tail lamp.
  6. Ignition OFF, exterior lamps OFF, test for less than 5.0 ohms between the ground circuit terminal C and ground. If greater than the specified range, test the ground circuit for an open/high resistance.
  7. Connect a test lamp between the control circuit terminal E and ground.
  8. Command the Backup Lamps ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states. If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the BCM. If the test lamp is always OFF, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM.
  9. If all circuits test normal, replace the tail lamp.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Tail Lamp Replacement (Sedan, V-Series)»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system) or «Tail Lamp Replacement (Wagon)»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system)
  2. «Inside Rearview Mirror Replacement»(/cadillac/cts/ii-2007-2014/remont/mirrors/#mirror-system)
  3. «Control Module References»(/cadillac/cts/ii-2007-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM replacement, setup, and programming
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Dome Lamp Switch Signal222
Left Front Door Open Switch Signal333
Left Rear Door Open Switch Signal333
Right Front Door Open Switch Signal333
Right Rear Door Open Switch Signal333
Courtesy Lamp High Control - Driver DoorB2555 021B2555 01
Courtesy Lamp High Control - Passenger DoorB2555 021B2555 01
Courtesy Lamp Control11
Inadvertent Power Control111
Courtesy Lamp Low Control - Driver Door1
Courtesy Lamp Low Control - Passenger Door1
I/P Dimmer Switch Ground2
LH Vanity Mirror Courtesy Lamp Ground1
Trunk Courtesy Lamp Ground1
Overhead Console Courtesy Lamp Ground1
Rear Dome Lamp Ground1
RH Vanity Mirror Courtesy Lamp Ground1
1. Courtesy Lamps Malfunction 2. Dome Lamp Switch Malfunction 3. Door Open Switch Malfunction

The body control module (BCM) applies battery voltage to the courtesy lamps through the courtesy lamp supply voltage circuit. When any door is opened, the jam switch contacts close and the BCM receives a door-open input. If the BCM receives a door lock or unlock input or a rear hatch open input, the BCM will activate the courtesy lamp supply voltage circuit, providing battery voltage to all of the instrument panel (I/P) courtesy lamps, dome lamps, rearview mirror lamps, and rear compartment lamps. The BCM also provides a serial data message to the driver door module (DDM) and front passenger door module (PDM) to apply battery voltage to the door courtesy lamps. In the event that any of these lamps were to remain illuminated for more than 20 minutes with the ignition switch in the OFF position, the BCM will deactivate the inadvertent power courtesy lamp control circuit to prevent a total battery discharge condition.

Battery voltage must be between 9-16 V.

B2555 01

The DDM or PDM detects a short to voltage in the courtesy lamp high control circuit.

B2555 02

The DDM or PDM detects a short to ground in the courtesy lamp high control circuit.

The affected door courtesy lamp will not illuminate or remain illuminated depending on the fault that is present.

  1. The condition responsible for setting the DTC no longer exists.
  2. A history DTC will clear once 100 consecutive malfunction-free ignition cycles have occurred.

After clearing the DTC, the ignition has to be cycled ON and OFF before the inoperative courtesy lamp will operate.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition OFF, disconnect the harness connector at the appropriate front door courtesy lamp.
  2. Ignition ON, test for less than 25.0 ohms between the ground circuit terminal B and ground. If greater than the specified range, test the low reference circuit for a short to voltage or an open/high resistance.
  3. Connect a test lamp between the control circuit terminal A and the ground circuit terminal B.
  4. Command the Courtesy Lamps ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states. If the test lamp is always ON, test the high control circuit for a short to voltage. If the circuit tests normal, replace the BCM. If the test lamp is always OFF, test the high control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM.
  5. If all circuits test normal, replace the front door courtesy lamp.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Door Lamp Replacement»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system)
  2. «Door Courtesy Lamp and Reflector Replacement»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system)
  3. «Control Module References»(/cadillac/cts/ii-2007-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM replacement, setup, and programming
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Flash to Pass Switch Signal111
Headlamp Switch High Beam Signal111
Headlamp Switch Headlamps ON SignalB257A 0011
Headlamp Switch Headlamps OFF SignalB257A 0011
Headlamp High Beam Relay Control11B2580 00
Headlamp Low Beam Relay Control11B2575 00
LF High Beam Headlamp Control111
LF Low Beam Headlamp Control111
RF High Beam Headlamp Control111
RF Low Beam Headlamp Control111
LF Headlamp Ground1
RF Headlamp Ground1
Turn Signal/Multifunction Switch Ground1
1. Headlamps Malfunction

When the turn signal/multifunction switch is placed in the headlamp position, ground is applied to the body control module (BCM) through the headlamp low beam signal circuit. The BCM then applies ground to the headlamp low beam relay control circuit which energizes the low beam relay. With the low beam relay energized, the switch contacts close allowing battery voltage to flow through the LOW BEAM fuses to the low beam headlamps.

  1. Battery voltage must be between 9-16 V.
  2. Headlamps ON.

The BCM detects a short to voltage in the headlamp low beam relay control circuit.

The low beam headlamps will not operate.

  1. The condition responsible for setting the DTC no longer exists.
  2. A history DTC will clear once 100 consecutive malfunction-free ignition cycles have occurred.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition OFF, disconnect the low beam relay.
  2. Connect a test lamp between the control circuit terminal 86 and the B+ circuit terminal 85.
  3. Command the Low Beams ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states. If the test lamp is always ON, test the control circuit for a short to ground. If the circuit tests normal, replace the BCM. If the test lamp is always OFF, test the control circuit for a short to voltage or open/high resistance. If the circuit tests normal, replace the BCM.
  4. If all circuits test normal, replace the low beam relay.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Underhood Electrical Center or Junction Block Replacement»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-repair-instructions)
  2. «Relay Replacement (Attached to Wire Harness)»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-repair-instructions) or «Relay Replacement (Within an Electrical Center)»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-repair-instructions)
  3. «Control Module References»(/cadillac/cts/ii-2007-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM replacement, setup, and programming
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of the diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Flash to Pass Switch Signal111
Headlamp Switch High Beam Signal111
Headlamp Switch Headlamps ON SignalB257A 0011
Headlamp Switch Headlamps OFF SignalB257A 0011
Headlamp High Beam Relay Control11B2580 00
Headlamp Low Beam Relay Control11B2575 00
LF High Beam Headlamp Control111
LF Low Beam Headlamp Control111
RF High Beam Headlamp Control111
RF Low Beam Headlamp Control111
LF Headlamp Ground1
RF Headlamp Ground1
Turn Signal/Multifunction Switch Ground1
1. Headlamps Malfunction

When the turn signal/multifunction switch is placed in the AUTO position, the body control module (BCM) receives a ground signal through the headlamp switch headlamps OFF signal circuit. The turn signal/multifunction switch headlamps ON signal circuit and the park lamp switch signal circuit are both open and have no ground signal. When the turn signal/multifunction switch is placed in the PARK or HEAD position, the BCM will receive a ground signal through the headlamp switch headlamps ON signal circuit and the park lamp switch signal circuit. The headlamp switch headlamps OFF signal circuit will be open and have no ground signal.

Battery voltage must be between 9-16 V.

The BCM detects a short to ground on the headlamp switch headlamps OFF signal circuit or the headlamp switch headlamps ON signal circuit.

  1. When DTC B257A 00 is present on the headlamp switch headlamps OFF signal circuit, the low beam headlamps are always ON in the AUTO position. The headlamp switch operates in all positions other than AUTO. The AUTO headlamp defeat is inoperative.
  2. When DTC B257A 00 is present on the headlamp switch headlamps ON signal circuit, the low beam headlamps are always ON. The BCM disregards all headlamp switch inputs.
  1. The condition responsible for setting the DTC no longer exists.
  2. A history DTC will clear once 100 consecutive malfunction-free ignition cycles have occurred.

Schematic Reference

  1. «Headlights/Daytime Running Lights (DRL) Schematics»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system)
  2. «Exterior Lights Schematics»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system)

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition OFF, disconnect the X1 harness connector at the BCM.
  2. Connect a test lamp between B+ and the signal circuit terminal 23.
  3. Cycle the headlamp switch between the AUTO and OFF positions. The test lamp should turn ON and OFF as the switch is cycled. If the test lamp is always OFF, test the signal circuit for a short to voltage or an open/high resistance. If the circuit test normal, replace the turn signal/multifunction switch. If the test lamp is always ON, test the signal circuit for a short to ground. If the circuit test normal, replace the turn signal/multifunction switch.
  4. Ignition OFF, disconnect the X2 harness connector at the BCM.
  5. Connect a test lamp between B+ and the signal circuit terminal 12.
  6. Cycle the headlamp switch between the HEAD and OFF positions. The test lamp should turn ON and OFF as the switch is cycled. If the test lamp is always OFF, test the signal circuit for a short to voltage or an open/high resistance. If the circuit test normal, replace the turn signal/multifunction switch. If the test lamp is always ON, test the signal circuit for a short to ground. If the circuit test normal, replace the turn signal/multifunction switch.
  7. Connect a test lamp between B+ and the signal circuit terminal 8.
  8. Cycle the headlamp switch between the PARK and OFF positions. The test lamp should turn ON and OFF as the switch is cycled. If the test lamp is always OFF, test the signal circuit for a short to voltage or an open/high resistance. If the circuit test normal, replace the turn signal/multifunction switch. If the test lamp is always ON, test the signal circuit for a short to ground. If the circuit test normal, replace the turn signal/multifunction switch.
  9. If all circuits test normal, replace the BCM.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Turn Signal Multifunction Switch Replacement»(/cadillac/cts/ii-2007-2014/remont/steering-column-switches/#steering-wheel-steering-column)
  2. «Control Module References»(/cadillac/cts/ii-2007-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM replacement, setup, and programming
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Flash to Pass Switch Signal111
Headlamp Switch High Beam Signal111
Headlamp Switch Headlamps ON SignalB257A 0011
Headlamp Switch Headlamps OFF SignalB257A 0011
Headlamp High Beam Relay Control11B2580 00
Headlamp Low Beam Relay Control11B2575 00
LF High Beam Headlamp Control111
LF Low Beam Headlamp Control111
RF High Beam Headlamp Control111
RF Low Beam Headlamp Control111
LF Headlamp Ground1
RF Headlamp Ground1
Turn Signal/Multifunction Switch Ground1
1. Headlamps Malfunction

When the turn signal/multifunction switch is placed in the headlamps high or flash to pass (FTP) position, ground is applied to the body control module (BCM) through the headlamp high beam signal circuit or the flash to pass switch signal circuit. The BCM applies ground to the headlamp high beam relay control circuit which energizes the high beam relay. With the high beam relay energized, the switch contacts close allowing battery voltage to flow through the HI BEAM fuses to the high beam headlamps.

  1. Battery voltage must be between 9-16 V.
  2. Headlamps ON.

The BCM detects a short to voltage in the headlamp high beam relay control circuit.

The high beam headlamps and flash to pass (FTP) will not operate.

  1. The condition responsible for setting the DTC no longer exists.
  2. A history DTC will clear once 100 consecutive malfunction-free ignition cycles have occurred.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition OFF, disconnect the high beam relay.
  2. Connect a test lamp between the control circuit terminal 86 and the B+ circuit terminal 85.
  3. Command the High Beams ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states. If the test lamp is always ON, test the control circuit for a short to ground. If the circuit tests normal, replace the BCM. If the test lamp is always OFF, test the control circuit for a short to voltage or open/high resistance. If the circuit tests normal, replace the BCM.
  4. If all circuits test normal, replace the high beam relay.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Underhood Electrical Center or Junction Block Replacement»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-repair-instructions)
  2. «Relay Replacement (Attached to Wire Harness)»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-repair-instructions) or «Relay Replacement (Within an Electrical Center)»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-repair-instructions)
  3. «Control Module References»(/cadillac/cts/ii-2007-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM replacement, setup, and programming
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Park Lamp Switch ON Signal111
LT/POS/LP Relay Control11B2585 00
License Lamp Control111
Park Lamp Control111
License Lamp Ground1
Park Lamps - LF Ground1
Park Lamps - RF Ground1
Tail/Stop and Turn Signal Lamps - LR Ground1
Tail/Stop and Turn Signal Lamps - RR Ground1
Turn Signal/Multifunction Switch Ground1
1. Park, License, and/or Tail Lamps Malfunction

Battery positive voltage is applied at all times to both the coil and switch sides of the LT/POS/LP relay located in the rear fuse block. The turn signal/multifunction switch is suppled with ground at all times. When the headlamp switch is placed in either the HEAD or PARK position, ground is applied to the park lamp signal circuit to the body control module (BCM). The BCM responds by applying ground to the park lamp relay control circuit. This energizes the park lamp relay coil causing the relay switch contacts to close allowing battery voltage to flow through the LT/POS/LP and RT/POS/LP fuses to all of the park, tail, license, and marker lamps.

  1. Battery voltage must be between 9-16 V.
  2. Park lamps ON.

The BCM detects a short to voltage in the park lamp relay control circuit.

The park lamps will not operate.

  1. The condition responsible for setting the DTC no longer exists.
  2. A history DTC will clear once 100 consecutive malfunction-free ignition cycles have occurred.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition OFF, disconnect the LT/POS/LP relay.
  2. Ignition ON, verify a test lamp does not illuminate between the control circuit terminal 87 and ground. If the test lamp illuminates, test the control circuit for a short to voltage.
  3. Verify a test lamp illuminates between the B+ circuit terminal 30 and ground. If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance. If the circuit tests normal and the B+ circuit fuse is open, test the control circuit terminal 87 for a short to ground. If the circuit tests normal, test or replace the LT/POS/LP relay.
  4. Verify a test lamp illuminates between the B+ circuit terminal 85 and ground. If the test lamp does not illuminate, test the B+ circuit for an open/high resistance.
  5. Connect a test lamp between the B+ circuit terminal 85 and the control circuit terminal 86.
  6. Command the Parking Lamps ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states. If the test lamp is always ON, test the control circuit for a short to ground. If the circuit tests normal, replace the BCM. If the test lamp is always OFF, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the BCM.
  7. If all circuits test normal, replace the LT/POS/LP relay.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Relay Replacement (Attached to Wire Harness)»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-repair-instructions) or «Relay Replacement (Within an Electrical Center)»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-repair-instructions)
  2. «Control Module References»(/cadillac/cts/ii-2007-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM replacement, setup, and programming
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Ambient Light Senor SignalB2645 03B2645 07B2645 07
Ambient Light Senor Low Reference111
DRL Relay ControlB2600 00B2600 001
LF Low Beam Headlamp Control223
RF Low Beam Headlamp Control445
LF Headlamp Ground2
RF Headlamp Ground4
1. Daytime Running Lamps Malfunction 2. Left Headlamp Inoperable 3. Left Headlamp Always ON 4. Right Headlamp Inoperable 5. Right Headlamp Always ON

The ambient light sensor is a light sensitive transistor that varies the voltage signal to the body control module (BCM) based on outside lighting conditions. When the ambient light sensor indicates daytime conditions, the body control module (BCM) grounds the DRL relay control circuit causing voltage to flow from the DRL fuse which energizes the DRL relay. With the DRL relay energized, the switch contacts close and voltage is applied to the left and right low beam headlamps. Any function or condition that turns on the headlamps will cancel DRL operation.

Battery voltage must be between 9-16 V.

The BCM detects a short to voltage in the DRL relay control circuit.

The DRLs will not operate.

  1. The condition responsible for setting the DTC no longer exists.
  2. A history DTC will clear once 100 consecutive malfunction-free ignition cycles have occurred.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

Ignition ON, command the Daytime Running Lamps ON and OFF with a scan tool. The daytime running lamps should turn ON and OFF when changing between the commanded states.

  1. Ignition OFF, disconnect the daytime running lamp relay.
  2. Ignition ON, verify that a test lamp does not illuminate between the control circuit terminal 87 and ground. If the test lamp illuminates, test the control circuit for a short to voltage.
  3. Verify that a test lamp illuminates between the B+ circuit terminal 85 and ground. If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.
  4. Verify that a test lamp illuminates between the B+ circuit terminal 30 and ground. If the test lamp does not illuminate, test the B+ circuit for an open/high resistance.
  5. Disconnect the harness connector at the appropriate daytime running lamp.
  6. Test for less than 5 ohms between the ground circuit terminal B and ground If greater than the specified range, test the ground circuit for an open/high resistance.
  7. Connect the harness connector at the daytime running lamp.
  8. Connect a 10 A fused jumper wire between the B+ circuit terminal 30 and the control circuit terminal 87. Verify the daytime running lamp is activated. If the daytime running lamp does not activate, test the control circuit for an open/high resistance. If the circuit tests normal, replace the daytime running lamp.
  9. Connect a test lamp between the B+ circuit terminal 85 and the control circuit terminal 86.
  10. Command the Daytime Running Lamp ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states. If the test lamp is always ON, test the control circuit for a short to ground. If the circuit tests normal, replace the BCM. If the test lamp is always OFF, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the BCM.
  11. If all circuits test normal, replace the daytime running lamp relay.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Headlamp Assembly or Headlamp Bulb and/or Cornering, Sidemarker, Park, Turn Signal Bulb Replacement (TT6)»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system) or «Headlamp Assembly or Headlamp Bulb and/or Cornering, Sidemarker, Park, Turn Signal Bulb Replacement (TT7)»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system) or «Headlamp Assembly or Headlamp Bulb and/or Cornering, Sidemarker, Park, Turn Signal Bulb Replacement (TT8)»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system__headlamp-assembly-or-headlamp-bulb-andor) or «Headlamp Assembly or Headlamp Bulb and/or Cornering, Sidemarker, Park, Turn Signal Bulb Replacement (Without TT6/TT7/TT8/T84/T85)»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system)
  2. «Relay Replacement (Attached to Wire Harness)»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-repair-instructions) or «Relay Replacement (Within an Electrical Center)»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-repair-instructions)
  3. «Control Module References»(/cadillac/cts/ii-2007-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM replacement, setup, and programming
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Body Control Module (BCM) 1 Fuse B+B1395 03B1395 03
Body Control Module (BCM) 7 Fuse B+B2652 00B2652 00
I/P Dimmer Switch SignalB1395 0311
I/P Lamps Dimmer Switch SignalB2652 0011
Indicator Dimming ControlB2625 0011
LED Backlight Dimming ControlB2610 0011
I/P Dimming Voltage ReferenceB1395 0311
I/P Dimmer Switch Ground1
1. Interior Backlighting Malfunction

The instrument panel (I/P) lamp dimmer switch is used to increase and decrease the brightness of the interior backlighting components. The I/P dimmer switch provides a voltage signal that will increase as the brightness of the lights are increased and decrease as the brightness of the lights are decreased. The body control module (BCM) provides a low reference signal and a B+ voltage reference to the I/P dimmer switch. When the I/P dimmer switch is placed in the desired position, the dimmed voltage setting is applied from the I/P dimmer switch through the I/P dimmer switch signal circuit to the BCM. The BCM interprets the signal and applies the dimmed voltage to the I/P lamps supply voltage circuit and the interior backlighting components dim to the requested level.

  1. Battery voltage must be between 9-16 V.
  2. Park lamps ON.

The BCM detects a short to ground in the LED backlight dimming control circuit.

The BCM will not dim or illuminate any indicators supplied by the LED backlight dimming control circuit.

  1. The condition responsible for setting the DTC no longer exists.
  2. A history DTC will clear once 100 consecutive malfunction-free ignition cycles have occurred.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

Note. Each back lighted component may need to be disconnected to isolate a short to voltage or short to ground. Use the schematic to identify the following: Back lighted components the vehicle is equipped with. Component locations on the back lighting dimming control circuit Each component's control and ground circuit terminals

  1. Ignition OFF, disconnect the harness connector at any component with inoperative backlighting.
  2. Ignition OFF, scan tool disconnected, interior lamps OFF, doors CLOSED, test for less than 5 ohms between the ground circuit and ground. If greater than the specified value, test the ground circuit for an open/high resistance.
  3. Connect a test lamp between the control circuit and ground.
  4. Command the Incandescent Dimming ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states. If the test lamp is always OFF, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM. If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the BCM.
  5. If all circuits test normal, test or replace the component with the inoperative backlighting.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. Refer to the appropriate replacement procedure for the component causing the condition
  2. «Control Module References»(/cadillac/cts/ii-2007-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM replacement, setup, and programming
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Body Control Module (BCM) 3 Fuse B+B2615 00B2615 00
Body Control Module (BCM) 7 Fuse B+B2652 00B2652 00
I/P Dimming Voltage ReferenceB1395 0311
I/P Dimmer Switch SignalB1395 0311
I/P Lamps Dimmer Switch SignalB2652 0011
Courtesy Lamps ControlB2615 0022
Indicator Dimming ControlB2625 0011
LED Backlight Dimming ControlB2610 0011
I/P Dimmer Switch Ground1
1. Interior Backlighting Malfunction 2. Courtesy Lamps Malfunction

The body control module (BCM) applies battery voltage to the courtesy lamps through the courtesy lamp supply voltage circuit. When any door is opened, the jam switch contacts close and the BCM receives a door-open input. If the BCM receives a door lock or unlock input or a rear hatch open input, the BCM will activate the courtesy lamp supply voltage circuit, providing battery voltage to all of the instrument panel (I/P) courtesy lamps, rearview mirror lamps, and rear compartment lamps. The BCM also provides a serial data message to the driver door module (DDM) and front passenger door module (PDM) to apply battery voltage to the exterior courtesy lamps. In the event that any of these lamps were to remain illuminated for more than 20 minutes with the ignition switch in the OFF position, the BCM will deactivate the inadvertent power courtesy lamp control circuit to prevent a total battery discharge condition.

Battery voltage must be between 9-16 V.

DTC B2615 00 will set for the following conditions

  1. The BCM detects a short to ground in the courtesy lamps voltage supply circuit.
  2. The BCM detects a short to ground or an open/high resistance in the BCM 3 fuse B+ circuit.

The BCM will not illuminate any courtesy lamps supplied by the courtesy lamps voltage supply circuit.

  1. The condition responsible for setting the DTC no longer exists.
  2. A history DTC will clear once 100 consecutive malfunction-free ignition cycles have occurred.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition OFF, disconnect the harness connector at any component with inoperative backlighting.
  2. Ignition OFF, scan tool disconnected, interior lamps OFF, doors CLOSED, test for less than 5 ohms between the ground circuit and ground. If greater than the specified value, test the ground circuit for an open/high resistance.
  3. Connect a test lamp between the control circuit and ground.
  4. Command the Incandescent Dimming ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states. If the test lamp is always OFF, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM. If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the BCM.
  5. If all circuits test normal, test or replace the component with the inoperative backlighting.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. Refer to the appropriate replacement procedure for the component causing the condition.
  2. «Control Module References»(/cadillac/cts/ii-2007-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM replacement, setup, and programming
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Accent Lamp ControlB261A 0021
Accent Lamp Ground2
1. Interior Accent Lighting Always ON 2. Interior Accent Lighting Always OFF

The instrument panel (I/P) dimmer switch is used to increase and decrease the brightness of the interior backlighting components. The I/P dimmer switch provides a voltage signal that will increase as the brightness of the light are increased and decrease as the brightness of the lights are decreased. The body control module (BCM) provides a low reference signal and a B+ voltage reference to the I/P dimmer switch. When the I/P dimmer switch is placed in the desired position, the dimmed voltage setting is applied from the I/P dimmer switch through the I/P dimmer switch signal circuit to the BCM. The BCM interprets the signal and applies the dimmed voltage to the individual accent lamps via the accent lamps control circuit. The BCM also sends a serial data message to the driver and front passenger door control modules requesting the accent lamps on both doors be dimmed to the requested level. The driver and front passenger door modules respond by applying the appropriate voltage for the requested dim level to the accent lights.

  1. Battery voltage must be between 9-16 V.
  2. Park lamps ON.

The BCM detects a short to ground in the accent lamp control circuit.

The BCM will not illuminate the accent lamps supplied by the accent lamp control circuit.

  1. The condition responsible for setting the DTC no longer exists.
  2. A history DTC will clear once 100 consecutive malfunction-free ignition cycles have occurred.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

Note. Each back lighted component may need to be disconnected to isolate a short to voltage or short to ground. Use the schematic to identify the following: Back lighted components the vehicle is equipped with. Component locations on the back lighting dimming control circuit. Each components control and ground circuit terminals.

  1. Ignition OFF, disconnect the harness connector at any component with inoperative backlighting.
  2. Ignition OFF, scan tool disconnected, interior lamps OFF, doors CLOSED, test for less than 5 ohms between the ground circuit and ground. If greater than the specified value, test the ground circuit for an open/high resistance.
  3. Connect a test lamp between the control circuit and ground.
  4. Command the Incandescent Dimming control ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states. If the test lamp is always OFF, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM. If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the BCM.
  5. If all circuits test normal, test or replace the component with the inoperative backlighting.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. Refer to the appropriate replacement procedure for the component causing the condition.
  2. «Control Module References»(/cadillac/cts/ii-2007-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM replacement, setup, and programming
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Body Control Module (BCM) 1 Fuse B+B1395 03B1395 03
Body Control Module (BCM) 7 Fuse B+B2652 00B2652 00
I/P Dimming Voltage ReferenceB1395 0311
I/P Dimmer Switch SignalB1395 0311
I/P Lamps Dimmer Switch SignalB2652 0011
Indicator Dimming ControlB2625 0011
LED Backlight Dimming ControlB2610 0011
I/P Dimmer Switch Ground1
1. Interior Backlighting Malfunction

The instrument panel (I/P) dimmer switch is used to increase and decrease the brightness of the interior backlighting components. The I/P dimmer switch provides a voltage signal that will increase as the brightness of the lights are increased and decrease as the brightness of the lights are decreased. The body control module (BCM) provides a low reference signal and a B+ voltage reference to the I/P dimmer switch. When the I/P dimmer switch is placed in the desired position, the dimmed voltage setting is applied from the I/P dimmer switch through the I/P dimmer switch signal circuit to the BCM. The BCM interprets the signal and applies the dimmed voltage to the I/P lamps supply voltage circuit and the interior backlighting components dim to the requested level.

  1. Battery voltage must be between 9-16 V.
  2. Park lamps ON.

The BCM detects a short to ground in the LED indicator dimming control circuit.

The BCM will not illuminate the LEDs supplied by the LED indicator dimming control circuit.

  1. The condition responsible for setting the DTC no longer exists.
  2. A history DTC will clear once 100 consecutive malfunction-free ignition cycles have occurred.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition OFF, disconnect the harness connector at any component with inoperative backlighting.
  2. Ignition OFF, scan tool disconnected, interior lamps OFF, doors CLOSED, test for less than 5 ohms between the ground circuit and ground. If greater than the specified value, test the ground circuit for an open/high resistance.
  3. Connect a test lamp between the control circuit and ground.
  4. Command the Incandescent Dimming ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states. If the test lamp is always OFF, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM. If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the BCM.
  5. If all circuits test normal, test or replace the component with the inoperative backlighting.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. Refer to the appropriate replacement procedure for the component causing the condition.
  2. «Control Module References»(/cadillac/cts/ii-2007-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM replacement, setup, and programming
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Ambient Light Sensor SignalB2645 03B2645 07B2645 07
Left Sun Load Sensor SignalB0183 06B0183 06B0183 06
Right Sun Load Sensor SignalB0188 06B0188 06B0188 06
Daytime Running Lamp - Left Control222
Daytime Running Lamp - Right Control222
Headlamp - Left Front Low Beam Control111
Headlamp - Right Front Low Beam Control111
Ambient Light Sensor Low ReferenceB2645 07B0183 06, B0188 06
Daytime Running Lamp - Left Ground2
Daytime Running Lamp - Right Ground2
Headlamp - Left Front Ground1
Headlamp - Right Front Ground1
1. Headlamps Malfunction 2. Daytime Running Lamps Malfunction

The ambient light sensor is used to monitor outside lighting conditions. The ambient light sensor provides a voltage signal that will vary between 0.2 and 4.9 V depending on outside lighting conditions. The HVAC control module provides a low reference ground and 5 V reference signals to the ambient light sensor. The body control module (BCM) monitors the ambient light sensor signal circuit to determine if outside lighting conditions are correct for either daytime running lights (DRL) or automatic lamp control (ALC) when the headlamp switch is in the AUTO position. In daylight conditions the BCM will command the DRLs ON. During low light conditions the BCM will command the low beam headlamps ON. Any function or condition that turns on the headlamps will cancel DRL operation.

Battery voltage must be between 9-16 V.

B2645 03

The BCM detects a short to ground in the ambient light sensor signal circuit.

B2645 07

The BCM detects a short to voltage or an open/high resistance in the ambient light sensor signal circuit.

  1. Automatic lamp control (ALC) is inoperative.
  2. The BCM defaults to low light status and commands the low beam headlamps ON.
  1. The condition responsible for setting the DTC no longer exists.
  2. A history DTC will clear once 100 consecutive malfunction-free ignition cycles have occurred.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition OFF, disconnect the harness connector at the ambient light/sunload sensor.
  2. Ignition OFF, scan tool OFF, doors CLOSED, test for less than 10.0 ohms between the low reference circuit terminal C and ground. If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the HVAC control module.
  3. Ignition ON, verify the scan tool Ambient Light Sensor parameter is greater than 4.65 V. If less than the specified range, test the signal circuit terminal D for a short to ground. If the circuit tests normal, replace the BCM.
  4. Install a 3 A fused jumper wire between the signal circuit terminal D and the low reference circuit terminal C. Verify the scan tool Ambient Light Sensor parameter is less than 0.196 V. If greater than the specified range, test the signal circuit for a short to voltage an open/high resistance. If the circuit tests normal, replace the BCM.
  5. If all circuits test normal, replace the ambient light/sunload sensor.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Headlamp Automatic Control Ambient Light Sensor Replacement»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system)
  2. «Control Module References»(/cadillac/cts/ii-2007-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM or HVAC control module replacement, setup, and programming
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Body Control Module (BCM) 1 Fuse B+B1395 03B1395 03
Body Control Module (BCM) 7 Fuse B+B2652 00B2652 00
I/P Dimming Voltage ReferenceB1395 0311
I/P Dimmer Switch SignalB1395 0311
I/P Lamps Dimmer Switch SignalB2652 0011
Indicator Dimming ControlB2625 0011
LED Backlight Dimming ControlB2610 0011
I/P Dimmer Switch Ground1
1. Interior Backlighting Malfunction

The instrument panel (I/P) lamp dimmer switch is used to increase and decrease the brightness of the interior backlighting components. The I/P dimmer switch provides a voltage signal that will increase as the brightness of the lights are increased and decrease as the brightness of the lights are decreased. The body control module (BCM) provides a low reference signal and a B+ voltage reference to the I/P dimmer switch. When the I/P dimmer switch is placed in the desired position, the dimmed voltage setting is applied from the I/P dimmer switch through the I/P dimmer switch signal circuit to the BCM. The BCM interprets the signal and applies the dimmed voltage to the I/P lamps supply voltage circuit and the interior backlighting components dim to the requested level.

  1. Battery voltage must be between 9-16 V.
  2. Park lamps ON.

DTC B2652 00 will set for the following conditions

  1. The BCM detects a short to ground in the I/P lamps dimmer switch signal circuit.
  2. The BCM detects a short to ground or an open/high resistance in the BCM 7 fuse B+ circuit.

The BCM will not DIM or illuminate any I/P lamps supplied by the I/P lamps dimmer switch signal circuit.

  1. The condition responsible for setting the DTC no longer exists.
  2. A history DTC will clear once 100 consecutive malfunction-free ignition cycles have occurred.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition OFF, disconnect the harness connector at any component with inoperative backlighting.
  2. Ignition OFF, scan tool disconnected, interior lamps OFF, doors CLOSED, test for less than 5 ohms between the ground circuit and ground. If greater than the specified value, test the ground circuit for an open/high resistance.
  3. Connect a test lamp between the control circuit and ground.
  4. Command the Incandescent Dimming ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states. If the test lamp is always OFF, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM. If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the BCM.
  5. If all circuits test normal, test or replace the component with the inoperative backlighting.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. Refer to the appropriate replacement procedure for the component causing the condition.
  2. «Control Module References»(/cadillac/cts/ii-2007-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM replacement, setup, and programming
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Headlamp Leveling Sensor 5 V Reference - FrontB3410 02B3410 02B3410 01
Headlamp Leveling Sensor 5 V Reference - RearB3420 02B3420 02B3420 01
Headlamp Leveling Sensor Signal - FrontB3410 03B3410 03B3410 07
Headlamp Leveling Sensor Signal - RearB3420 03B3420 03B3420 07
Headlamp Leveling Sensor Low Reference - Front11
Headlamp Leveling Sensor Low Reference - Rear11
1. Headlamp Leveling Malfunction

The front and rear suspension position sensors provide the headlamp control module with front and rear suspension position information. Each sensor receives a 5 V reference, signal, and low reference circuits from the headlamp control module. The sensors are connected to the control arms at the front and rear suspension. As the vehicle travels, the suspension compresses and rebounds moving the suspension position sensor arms. This causes the signal output of the sensors to change. The headlamp control module compares the information from the front and rear suspension position sensors and adjusts the headlamp leveling as needed.

  1. Battery voltage must be between 9-16 V.
  2. Ignition in the ON or RUN position.
  3. Headlamps ON.

B3410 01 or B3420 01

The headlamp control module detects a short to voltage or an open/high resistance on the 5 V reference circuit.

B3410 02 or B3420 02

The headlamp control module detects a short to ground on the 5 V reference circuit.

B3410 03 or B3420 03

The headlamp control module detects a short to ground or an open/high resistance on the sensor signal circuit.

B3410 07 or B3420 07

The headlamp control module detects a short to voltage on the sensor signal circuit.

  1. The headlamp control module disables the headlamp leveling system.
  2. The driver information center (DIC) will display AFL Lamps Need Service.
  3. On vehicles equipped with both AFL and headlamp leveling, the AFL system will remain active.
  1. The condition responsible for setting the DTC no longer exists and the ignition is cycled.
  2. A history DTC will clear once 50 consecutive malfunction-free cycles have occurred.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition OFF, disconnect the harness connector at the appropriate headlamp leveling sensor.
  2. Ignition OFF, test for less than 10.0 ohms between the low reference circuit terminal C and ground. If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the headlamp control module.
  3. Ignition ON, test for 4.8-5.2 V between the 5 V reference circuit terminal A and ground. If less than the specified range, test the 5 V reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the headlamp control module. If greater than the specified range, test the 5 V reference circuit for a short to voltage. If the circuit tests normal, replace the headlamp control module.
  4. Verify the appropriate scan tool Leveling Position Sensor parameter is less than 0.5 V. If greater than the specified range, test the signal circuit terminal B for a short to voltage. If the circuit tests normal, replace the headlamp control module.
  5. Install a 3 A fused jumper wire between the signal circuit terminal B and the 5 V reference circuit terminal A. Verify the appropriate scan tool Leveling Position Sensor parameter is greater than 4.8 V. If less than the specified range, test the signal circuit for short to ground or an open/high resistance. If the circuit tests normal, replace the headlamp control module.
  6. If all circuits test normal, replace the headlamp leveling sensor.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Headlamp Leveling Front Suspension Height Sensor Replacement»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system)
  2. «Headlamp Leveling Rear Suspension Height Sensor Replacement»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system)
  3. «Control Module References»(/cadillac/cts/ii-2007-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for headlamp control module replacement, setup, and programming
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Headlamp Leveling Motor Control Circuit 1 - LeftB3435 02B3435 00B3435 00B3435 39, B3435 54
Headlamp Leveling Motor Control Circuit 2 - LeftB3435 02B3435 00B3435 00B3435 39, B3435 54
Headlamp Leveling Motor Control Circuit 3 - LeftB3435 02B3435 00B3435 00B3435 39, B3435 54
Headlamp Leveling Motor Control Circuit 4 - LeftB3435 02B3435 00B3435 00B3435 39, B3435 54
Headlamp Leveling Motor Control Circuit 1 - RightB3440 02B3440 00B3440 00B3440 39, B3440 54
Headlamp Leveling Motor Control Circuit 2 - RightB3440 02B3440 00B3440 00B3440 39, B3440 54
Headlamp Leveling Motor Control Circuit 3 - RightB3440 02B3440 00B3440 00B3440 39, B3440 54
Headlamp Leveling Motor Control Circuit 4 - RightB3440 02B3440 00B3440 00B3440 39, B3440 54

Each headlamp assembly contains a headlamp leveling motor that is controlled by the headlamp control module. The front and rear suspension position sensors provide the electronic suspension control (ESC) module with suspension position information. Each sensor receives a 5 V reference, signal, and low reference circuits from the ESC. The sensors are connected to the control arms of the front and rear suspension. As the vehicle travels, the suspension compresses and rebounds moving the suspension position sensor arms. This causes the signal output of the sensor to change. The ESC sends the suspension position sensor values to the headlamp control module via serial data. The headlamp control module compares the information from both suspension position sensors and adjusts the headlamp leveling as needed. The headlamp control module is wired to each headlamp leveling motor with 4 directional motor control circuits.

  1. Battery voltage must be between 9-16 V.
  2. Ignition in the ON or RUN position.
  3. Headlamps ON.

B3435 00

The headlamp control module detects a short to voltage or an open/high resistance on any of the left motor control circuits.

B3435 02

The headlamp control module detects a short to ground on any of the left motor control circuits.

B3435 39

The headlamp control module detects an internal electronic failure.

B3435 54

The headlamp control module detects an overheating condition on any of the left motor control circuits.

B3440 00

The headlamp control module detects a short to voltage or an open/high resistance on any of the right motor control circuits.

B3440 02

The headlamp control module detects a short to ground on any of the right motor control circuits.

B3440 39

The headlamp control module detects an internal electronic failure.

B3440 54

The headlamp control module detects an overheating condition on any of the right motor control circuits.

  1. When DTC B3435 or DTC B3440 sets, the headlamp control module will attempt to return the lamps to a nominal position and disable all requests to all headlamp actuators.
  2. The driver information center (DIC) will display AFL Lamps Need Service.
  1. The condition responsible for setting the DTC no longer exists and the ignition is cycled.
  2. A history DTC will clear once 50 consecutive malfunction-free cycles have occurred.

Schematic Reference

  1. «Headlights/Daytime Running Lights (DRL) Schematics»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system)
  2. «Electronic Suspension Control Schematics»(/cadillac/cts/ii-2007-2014/remont/electronic-suspension/#suspension-control-system-suspension-damping)

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition OFF, disconnect the harness connector at the appropriate headlamp.
  2. Remove the AFS 15 A fuse.
  3. Ignition OFF, scan tool OFF, test for 10 ohms-25K ohms between each control circuit terminal listed below and ground. Headlamp leveling motor control terminal 1 Headlamp leveling motor control terminal 2 Headlamp leveling motor control terminal 3 Headlamp leveling motor control terminal 4 If greater than the specified range, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the headlamp control module. If less than the specified range, test the control circuit for a short to ground. If the circuit tests normal, replace the headlamp control module.
  4. Install the AFS 15 A fuse.
  5. Ignition ON, scan tool OFF, headlamps ON, verify that a test lamp does not illuminate between each control circuit terminal listed below and ground. Headlamp leveling motor control terminal 1 Headlamp leveling motor control terminal 2 Headlamp leveling motor control terminal 3 Headlamp leveling motor control terminal 4 If the test lamp illuminates, test the control circuit for a short to voltage. If the circuit tests normal, replace the headlamp control module.
  6. If all circuits test normal, replace the headlamp assembly.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Headlamp Assembly or Headlamp Bulb and/or Cornering, Sidemarker, Park, Turn Signal Bulb Replacement (TT6)»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system) or «Headlamp Assembly or Headlamp Bulb and/or Cornering, Sidemarker, Park, Turn Signal Bulb Replacement (TT7)»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system) or «Headlamp Assembly or Headlamp Bulb and/or Cornering, Sidemarker, Park, Turn Signal Bulb Replacement (TT8)»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system__headlamp-assembly-or-headlamp-bulb-andor) or «Headlamp Assembly or Headlamp Bulb and/or Cornering, Sidemarker, Park, Turn Signal Bulb Replacement (Without TT6/TT7/TT8/T84/T85)»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system)
  2. «Control Module References»(/cadillac/cts/ii-2007-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for headlamp control module replacement, setup, and programming
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Headlamp Leveling Motor Control Circuit 1 - LeftB3435 02B3435 00B3435 00B3435 39, B3435 54
Headlamp Leveling Motor Control Circuit 2 - LeftB3435 02B3435 00B3435 00B3435 39, B3435 54
Headlamp Leveling Motor Control Circuit 3 - LeftB3435 02B3435 00B3435 00B3435 39, B3435 54
Headlamp Leveling Motor Control Circuit 4 - LeftB3435 02B3435 00B3435 00B3435 39, B3435 54
Headlamp Leveling Motor Control Circuit 1 - RightB3440 02B3440 00B3440 00B3440 39, B3440 54
Headlamp Leveling Motor Control Circuit 2 - RightB3440 02B3440 00B3440 00B3440 39, B3440 54
Headlamp Leveling Motor Control Circuit 3 - RightB3440 02B3440 00B3440 00B3440 39, B3440 54
Headlamp Leveling Motor Control Circuit 4 - RightB3440 02B3440 00B3440 00B3440 39, B3440 54

Each headlamp assembly contains a headlamp leveling motor that is controlled by the headlamp control module. The front and rear suspension position sensors provide the headlamp control module with suspension position information. Each sensor receives a 5 V reference, signal, and low reference circuits from the headlamp control module. The sensors are connected to the control arms of the front and rear suspension. As the vehicle travels, the suspension compresses and rebounds moving the suspension position sensor arms. This causes the signal output of the sensor to change. The headlamp control module compares the information from both suspension position sensors and adjusts the headlamp leveling as needed. The headlamp control module is wired to each headlamp leveling motor with 4 directional motor control circuits.

  1. Battery voltage must be between 9-16 V.
  2. Ignition in the ON or RUN position.
  3. Headlamps ON.

The headlamp control module detects a short to voltage or an open/high resistance on any of the left motor control circuits.

The headlamp control module detects a short to ground on any of the left motor control circuits.

The headlamp control module detects an internal electronic failure.

The headlamp control module detects an overheating condition on any of the left motor control circuits.

The headlamp control module detects a short to voltage or an open/high resistance on any of the right motor control circuits.

The headlamp control module detects a short to ground on any of the right motor control circuits.

The headlamp control module detects an internal electronic failure.

The headlamp control module detects an overheating condition on any of the right motor control circuits.

  1. When DTC B3435 or DTC B3440 sets, the headlamp control module will attempt to return the lamps to a nominal position and disable all requests to all headlamp actuators.
  2. The driver information center (DIC) will display AFL Lamps Need Service.
  1. The condition responsible for setting the DTC no longer exists and the ignition is cycled.
  2. A history DTC will clear once 50 consecutive malfunction-free cycles have occurred.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition OFF, disconnect the harness connector at the appropriate headlamp.
  2. Remove the AFS 15 A fuse.
  3. Ignition OFF, scan tool OFF, test for 10 ohms -25k ohms between each control circuit terminal listed below and ground. Headlamp leveling motor control terminal 1 Headlamp leveling motor control terminal 2 Headlamp leveling motor control terminal 3 Headlamp leveling motor control terminal 4 If greater than the specified range, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the headlamp control module. If less than the specified range, test the control circuit for a short to ground. If the circuit tests normal, replace the headlamp control module.
  4. Install the AFS 15 A fuse.
  5. Ignition ON, scan tool OFF, headlamps ON, verify that a test lamp does not illuminate between each control circuit terminal listed below and ground. Headlamp leveling motor control terminal 1 Headlamp leveling motor control terminal 2 Headlamp leveling motor control terminal 3 Headlamp leveling motor control terminal 4 If the test lamp illuminates, test the control circuit for a short to voltage. If the circuit tests normal, replace the headlamp control module.
  6. If all circuits test normal, replace the headlamp assembly.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Headlamp Assembly or Headlamp Bulb and/or Cornering, Sidemarker, Park, Turn Signal Bulb Replacement (TT6)»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system) or «Headlamp Assembly or Headlamp Bulb and/or Cornering, Sidemarker, Park, Turn Signal Bulb Replacement (TT7)»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system) or «Headlamp Assembly or Headlamp Bulb and/or Cornering, Sidemarker, Park, Turn Signal Bulb Replacement (TT8)»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system__headlamp-assembly-or-headlamp-bulb-andor) or «Headlamp Assembly or Headlamp Bulb and/or Cornering, Sidemarker, Park, Turn Signal Bulb Replacement (Without TT6/TT7/TT8/T84/T85)»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system)
  2. «Control Module References»(/cadillac/cts/ii-2007-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for headlamp control module replacement, setup, and programming
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Body Control Module (BCM) 5 Fuse B+1, 21, 2
Body Control Module (BCM) 6 Fuse B+1, 21, 2
Brake Position Sensor 5 V ReferenceC0277 06, C0890 03C0277 061, 2
Stop Lamp Relay Switch B+ - European22
Brake Applied SignalC0297 00, P0571 0044
Brake Position Sensor SignalC0277 06C0277 06C0277 07C0277 09
Center High Mounted Stop Lamp (CHMSL) ControlB3884 002, 32, 3
Stop Lamp Relay Control - EuropeanB3445 002, 32, 3
Left Rear Stop/Turn Lamp Control1, 21, 21, 2
Right Rear Stop/Turn Lamp Control1, 21, 21, 2
Center High Mounted Stop Lamp (CHMSL) Ground33
Brake Position Sensor Low ReferenceC0277 071, 2
Left Rear Stop/Turn Lamp Ground1, 21, 2
Right Rear Stop/Turn Lamp Ground1, 21, 2
Stop Lamp Relay Ground - European22
1. Stop Lamps Malfunction - North America 2. Stop Lamps Malfunction - European 3. Center High Mounted Stop Lamp (CHMSL) Malfunction 4. Cruise Control Malfunction

North America

The brake pedal position sensor is used to sense the action of the driver application of the brake pedal. The brake pedal position sensor provides an analog voltage signal that will increase as the brake pedal is applied. The body control module (BCM) provides a low reference signal and a 5 V reference voltage to the brake pedal position sensor. When the variable signal reaches a voltage threshold indicating the brakes have been applied, the BCM will apply battery voltage to the right and left stop lamp control circuits, transmission control module (TCM), engine control module (ECM), and center high mounted stop lamp (CHMSL) control circuit.

European

The brake pedal position sensor is used to sense the action of the driver application of the brake pedal. The brake pedal position sensor provides an analog voltage signal that will increase as the brake pedal is applied. The body control module (BCM) provides a low reference signal and a 5 V reference voltage to the brake pedal position sensor. When the variable signal reaches a voltage threshold indicating the brakes have been applied, the BCM will apply battery voltage to stop lamp relay coil side control circuit, transmission control module (TCM), engine control module (ECM), and center high mounted stop lamp (CHMSL). When the stop lamp relay receives battery voltage from the BCM, the relay coil is energized and the stop lamp relay switch contacts close applying battery voltage from the STOP LAMPS fuse to illuminate the rear stop lamps and trailer stop lamps.

  1. Battery voltage must be between 9-16 V.
  2. Brakes APPLIED.

DTC B3445 00

The BCM detects a short to ground in the CHMSL control circuit when the stop lamps are being commanded ON.

DTC B3884 00

The BCM detects a short to ground in the CHMSL control circuit when the stop lamps are being commanded ON.

The BCM will not illuminate the CHMSL.

  1. The condition responsible for setting the DTC no longer exists.
  2. A history DTC will clear once 100 malfunction-free ignition cycles have occurred.

Note. The stop lamps will not illuminate unless the ignition is in the ON position. For more detailed information concerning stop lamp operation, refer to Exterior Lighting Systems Description and Operation .

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition OFF, disconnect the harness connector at the CHMSL.
  2. Ignition OFF, test for less than 5.0 ohms between the ground circuit terminal B and ground. If greater than the specified range, test the ground circuit for an open/high resistance.
  3. Connect a test lamp between the control circuit terminal A and the ground circuit terminal B.
  4. Ignition ON, turn the stop lamps ON and OFF by applying and releasing the brake pedal. The test lamp should turn ON and OFF when changing between the selected states. If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the BCM. If the test lamp is always OFF, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM.
  5. If all circuits test normal, replace the CHMSL.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «High Mount Stop Lamp Replacement (Sedan, V-Series)»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system) or «High Mount Stop Lamp Replacement (Wagon)»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system)
  2. «Control Module References»(/cadillac/cts/ii-2007-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM replacement, setup, and programming
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Rear Fog Lamp Switch SignalB3588 0222
Rear Fog Lamp Relay ControlB2540 02B2540 05B2540 05
Rear Fog Lamp Control111
Fog Lamp-LR Ground11
Fog Lamp-RR Ground11
Rear Fog Lamp Switch Ground22
1. Rear Fog Lamps Malfunction 2. Rear Fog Lamp Switch Malfunction

The rear fog lamp relay is supplied with battery voltage at all times from the REAR FOG fuse located in the rear fuse block. The rear fog lamp switch signal circuit is grounded momentarily by pressing the rear fog lamp switch. The body control module (BCM) energizes the rear fog lamp relay by applying ground to the rear fog lamp relay control circuit. When the rear fog lamp relay is energized, the relay switch contacts close and battery voltage is applied through the REAR FOG fuse to the rear fog lamp supply voltage circuit which illuminates the rear fog lamps.

Battery voltage must be between 9-16 V.

The BCM detects a short to ground in the rear fog lamp switch signal circuit.

The rear fog lamps will not operate when the park lamps are ON.

  1. The condition responsible for setting the DTC no longer exists.
  2. A history DTC will clear once 100 consecutive malfunction-free ignition cycles have occurred.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition OFF, disconnect the X1 harness connector at the turn signal/multifunction switch.
  2. Ignition OFF, verify a test lamp illuminates between B+ and the ground circuit terminal 10. If the test lamp does not illuminate, test the ground circuit for an open/high resistance.
  3. Ignition ON, verify the scan tool Rear Fog Lamp Switch parameter is Inactive. If not the specified value, test the signal circuit terminal 8 for a short to ground. If the circuit tests normal, replace the BCM.
  4. Install a 3 A fused jumper wire between the signal circuit terminal 8 and the ground circuit terminal 10. Verify the scan tool Rear Fog Lamp Switch parameter is Active. If not the specified value, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the BCM.
  5. If all circuits test normal, test or replace the turn signal/multifunction switch.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Turn Signal Multifunction Switch Replacement»(/cadillac/cts/ii-2007-2014/remont/steering-column-switches/#steering-wheel-steering-column)
  2. «Control Module References»(/cadillac/cts/ii-2007-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM replacement, setup, and programming
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
I/P Dimmer Switch B+ Voltage Reference1
I/P Dimmer Switch SignalB1395 03, B3600 03B2652 00, B3600 03B1395 07
I/P Dimmer Switch Ground1
1. Interior Backlighting Malfunction

The instrument panel (I/P) lamp dimmer switch is used to increase and decrease the brightness of the interior backlighting components. The I/P dimmer switch provides a voltage signal that will increase as the brightness of the lights are increased and decrease as the brightness of the lights are decreased. The body control module (BCM) provides a low reference signal and a B+ voltage reference to the I/P dimmer switch. When the I/P dimmer switch is placed in the desired position, the dimmed voltage setting is applied from the I/P dimmer switch through the I/P dimmer switch signal circuit to the BCM. The BCM interprets the signal and applies the dimmed voltage to the I/P lamps supply voltage circuit and the interior backlighting components dim to the requested level.

Battery voltage must be between 9-16 V.

The BCM detects a short to ground or an open/high resistance in the I/P dimmer switch signal circuit.

  1. The I/P dimmer switch will not operate.
  2. The I/P dimming lamps will not illuminate.
  1. The condition responsible for setting the DTC no longer exists.
  2. A history DTC will clear once 100 consecutive malfunction-free ignition cycles have occurred.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. With a scan tool clear the DTC.
  2. Ignition OFF, disconnect the harness connector at the I/P Dimmer switch.
  3. Ignition OFF, verify a test lamp illuminates between B+ and the ground circuit terminal 10. If the test lamp does not illuminate, test the ground circuit for an open/high resistance.
  4. Ignition ON, test for B+ between the voltage reference circuit terminal 5 and ground. If less than the specified value, test the voltage reference circuit for a short to ground or an open/high resistance. If the circuit test normal, replace the BCM.
  5. Verify the scan tool Dimming Control Signal parameter is less than 0.2 volts. If greater than the specified range, test the signal circuit terminal 9 for a short to voltage. If the circuit tests normal, replace the BCM.
  6. Install a 3 A fused jumper wire between the signal circuit terminal 9 and the voltage reference circuit terminal 5. Verify the scan tool Dimming Control Signal parameter is greater than 2.5 volts. If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM.
  7. If all circuits test normal, replace the I/P dimmer switch.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Instrument Panel Lamp Dimmer Switch Replacement»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system)
  2. «Control Module References»(/cadillac/cts/ii-2007-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM replacement, setup, and programming
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Body Control Module (BCM) 5 Fuse B+1, 21, 2
Body Control Module (BCM) 6 Fuse B+1, 21, 2
Brake Position Sensor 5 V ReferenceC0277 06, C0890 03C0277 061, 2
Stop Lamp Relay Switch B+ - European22
Brake Applied SignalC0297 00 and P0571 0044
Brake Position Sensor SignalC0277 06C0277 06C0277 07C0277 09
Center High Mounted Stop Lamp (CHMSL) ControlB3884 002, 32, 3
Stop Lamp Relay Control - EuropeanB3445 002, 32, 3
Left Rear Stop/Turn Lamp Control1, 21, 21, 2
Right Rear Stop/Turn Lamp Control1, 21, 21, 2
Brake Position Sensor Low ReferenceC0277 071, 2
Center High Mounted Stop Lamp (CHMSL) Ground33
Left Rear Stop/Turn Lamp Ground1, 21, 2
Right Rear Stop/Turn Lamp Ground1, 21, 2
Stop Lamp Relay Ground - European22
1. Stop Lamps Malfunction - North America 2. Stop Lamps Malfunction - European 3. Center High Mounted Stop Lamp (CHMSL) Malfunction 4. Cruise Control Malfunction

The brake pedal position sensor is used to sense the action of the driver application of the brake pedal. The brake pedal position sensor provides an analog voltage signal that will increase as the brake pedal is applied. The body control module (BCM) provides a low reference signal and a 5 V reference voltage to the brake pedal position sensor. When the variable signal reaches a voltage threshold indicating the brakes have been applied, the BCM will apply battery voltage to the right and left stop lamp control circuits, transmission control module (TCM), engine control module (ECM), and center high mounted stop lamp (CHMSL) control circuit.

The brake pedal position sensor is used to sense the action of the driver application of the brake pedal. The brake pedal position sensor provides an analog voltage signal that will increase as the brake pedal is applied. The body control module (BCM) provides a low reference signal and a 5 V reference voltage to the brake pedal position sensor. When the variable signal reaches a voltage threshold indicating the brakes have been applied, the BCM will apply battery voltage to stop lamp relay coil side control circuit, transmission control module (TCM), engine control module (ECM), and center high mounted stop lamp (CHMSL). When the stop lamp relay receives battery voltage from the BCM, the relay coil is energized and the stop lamp relay switch contacts close applying battery voltage from the STOP LAMPS fuse to illuminate the rear stop lamps and trailer stop lamps.

  1. Battery voltage must be between 9-16 V.
  2. Brakes APPLIED.

DTC C0277 06 will set for the following conditions

  1. The BCM detects a short to ground or an open/high resistance in the brake pedal position sensor signal circuit.
  2. The BCM detects a short to ground or an open/high resistance in the brake pedal position sensor 5 V reference circuit.

DTC C0277 07 will set for the following conditions

  1. The BCM detects a short to battery voltage in the brake pedal position sensor signal circuit.
  2. The BCM detects an open/high resistance in the brake pedal position sensor low reference circuit.

C0277 09

The BCM detects the brake pedal position sensor signal is changing faster than possible under normal operating conditions.

C0277 4B

The brake pedal position sensor home position is not learned.

  1. The Service Brake Assist indicator is commanded ON.
  2. If the DTC sets while the vehicle is running, the BCM will activate the brake lights when the vehicles transmission is not in the PARK position and the vehicle is not accelerating.
  3. For DTC C0277 4B the stop lamps may not activate at the expected brake pedal positions.
  1. The condition responsible for setting the DTC no longer exists.
  2. For DTC C0277 07 the ignition must be cycled before the code can be cleared.
  3. For DTC C0277 4B a successful brake pedal position sensor calibration has been performed.
  4. A history DTC will clear once 50 malfunction-free ignition cycles have occurred.
  5. A DTC will not clear the current status until the next ignition cycle.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

C0277 06 and C0277 07, C0890 03, and C0890 07

  1. Ignition OFF, disconnect the harness connector at the brake pedal position sensor.
  2. Ignition OFF, verify that a test lamp illuminates between B+ and the low reference circuit terminals listed below: Terminal A (LHD) Terminal C (RHD) If the test lamp does not illuminate, test the low reference circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the BCM.
  3. Ignition ON, test for 4.8-5.2 V between the 5 V reference circuit terminals listed below and ground: Terminal C (LHD) Terminal A (RHD) If less than the specified range, test the 5 V reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM. If greater than the specified range, test the 5 V reference circuit for a short to voltage. If the circuit tests normal, replace the BCM.
  4. Verify the scan tool BPP Sensor parameter is less than 100 counts. If greater than the specified range, test the signal circuit terminal B for a short to voltage. If the circuit tests normal, replace the BCM.
  5. Install a 3 A fused jumper wire between the signal circuit terminal B and the 5 V reference circuit terminals listed below. Verify the scan tool BPP Sensor parameter is greater than 400 counts. Terminal C (LHD) Terminal A (RHD) If less than the specified range, test the signal circuit for short to ground or an open/high resistance. If the circuit tests normal, replace the BCM.
  6. If all circuits test normal, replace the brake pedal position sensor.

C0277 09

  1. Replace the brake pedal position sensor.
  2. Perform the brake pedal position sensor recalibration procedure. Refer to «Brake Pedal Position Sensor Calibration»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system__brake-pedal-position-sensor-calibration) .
  3. Operate the vehicle within the Conditions for Running and Setting the DTC and verify the DTC does not reset. If the DTC resets, replace the BCM.

C0277 4B

  1. Verify that the DTC sets under the Conditions for Running and Setting.
  2. Perform the brake pedal position sensor recalibration procedure. Refer to «Brake Pedal Position Sensor Calibration»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system__brake-pedal-position-sensor-calibration) .
  3. Operate the vehicle within the conditions that the customer experienced and verify the DTC does not reset. If the DTC resets, replace the brake pedal position sensor.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Brake Pedal Position Sensor Replacement»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system__brake-pedal-position-sensor-replacement)
  2. «Brake Pedal Position Sensor Calibration»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system__brake-pedal-position-sensor-calibration)
  3. «Control Module References»(/cadillac/cts/ii-2007-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM replacement, setup, and programming
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Body Control Module (BCM) 5 Fuse B+1, 21, 2
Body Control Module (BCM) 6 Fuse B+1, 21, 2
Brake Position Sensor 5 V ReferenceC0277 06, C0890 03C0277 061, 2
Stop Lamp Relay Switch B+ - European22
Brake Applied SignalC0297 00, P0571 0044
Brake Position Sensor SignalC0277 06C0277 06C0277 07C0277 09
Center High Mounted Stop Lamp (CHMSL) ControlB3884 002, 32, 3
Stop Lamp Relay Control - EuropeanB3445 002, 32, 3
Left Rear Stop/Turn Lamp Control1, 21, 21, 2
Right Rear Stop/Turn Lamp Control1, 21, 21, 2
Brake Position Sensor Low ReferenceC0277 071, 2
Center High Mounted Stop Lamp (CHMSL) Ground33
Left Rear Stop/Turn Lamp Ground1, 21, 2
Right Rear Stop/Turn Lamp Ground1, 21, 2
Stop Lamp Relay Ground - European22
1. Stop Lamps Malfunction - North America 2. Stop Lamps Malfunction - European 3. Center High Mounted Stop Lamp (CHMSL) Malfunction 4. Cruise Control Malfunction

The brake pedal position sensor is used to sense the action of the driver application of the brake pedal. The brake pedal position sensor provides an analog voltage signal that will increase as the brake pedal is applied. The body control module (BCM) provides a low reference signal and a 5 V reference voltage to the brake pedal position sensor. When the variable signal reaches a voltage threshold indicating the brakes have been applied, the BCM will apply battery voltage to the right and left stop lamp control circuits, transmission control module (TCM), engine control module (ECM), and center high mounted stop lamp (CHMSL) control circuit.

The brake pedal position sensor is used to sense the action of the driver application of the brake pedal. The brake pedal position sensor provides an analog voltage signal that will increase as the brake pedal is applied. The body control module (BCM) provides a low reference signal and a 5 V reference voltage to the brake pedal position sensor. When the variable signal reaches a voltage threshold indicating the brakes have been applied, the BCM will apply battery voltage to stop lamp relay coil side control circuit, transmission control module (TCM), engine control module (ECM), and center high mounted stop lamp (CHMSL). When the stop lamp relay receives battery voltage from the BCM, the relay coil is energized and the stop lamp relay switch contacts close applying battery voltage from the STOP LAMPS fuse to illuminate the rear stop lamps and trailer stop lamps.

  1. Battery voltage must be between 9-16 V.
  2. Brakes APPLIED.

The BCM detects a short to ground in the brake applied signal circuit.

  1. The BCM stores the DTC to memory.
  2. The Service Brake Assist indicator is commanded ON.
  1. The condition responsible for setting the DTC no longer exists.
  2. A history DTC will clear once 50 malfunction-free ignition cycles have occurred.

Note. The stop lamps will not illuminate unless the ignition is in the ON position. For more detailed information concerning stop lamp operation, refer to Exterior Lighting Systems Description and Operation .

Verify that the brake pedal position sensor is properly calibrated.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition OFF, disconnect the X2 harness connector at the ECM.
  2. Connect a test lamp between the signal circuit terminal 52 and ground.
  3. Ignition ON, turn the stop lamps ON and OFF by applying and releasing the brake pedal. The test lamp should turn ON and OFF when changing between the selected states. If the test lamp is always ON, test the signal circuit for a short to voltage. If the circuit tests normal, replace the BCM. If the test lamp is always OFF, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM.
  4. Ignition OFF, connect a test lamp between the signal circuit terminal 52 at the ECM harness connector and the connector terminal at the ECM.
  5. Ignition ON, turn the stop lamps ON and OFF by applying and releasing the brake pedal. The test lamp should turn ON and OFF when changing between the selected states. If the test lamp does not turn ON and OFF when commanded, replace the ECM.
  6. Ignition OFF, connect the harness connector at the ECM.
  7. Disconnect the harness connector at the TCM.
  8. Connect a test lamp between the signal circuit terminal 6 and ground.
  9. Ignition ON, turn the stop lamps ON and OFF by applying and releasing the brake pedal. The test lamp should turn ON and OFF when changing between the selected states. If the test lamp is always ON, test the signal circuit for a short to voltage. If the circuit tests normal, replace the BCM. If the test lamp is always OFF, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM.
  10. If all circuits test normal, replace the TCM.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Brake Pedal Position Sensor Calibration»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system__brake-pedal-position-sensor-calibration)
  2. «Control Module References»(/cadillac/cts/ii-2007-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM, ECM, or TCM replacement, setup, and programming

Symptoms - Lighting

Note. The following steps must be completed before using a symptom table. Perform the Diagnostic System Check - Vehicle before using a symptom table in order to verify that all of the following conditions are true: There are no DTCs set. The control modules can communicate via the serial data link. Review the system description and operation in order to familiarize yourself with the system functions. Refer to the following: Exterior Lighting Systems Description and Operation Interior Lighting Systems Description and Operation

Visual/Physical Inspection

  1. Inspect for aftermarket devices which could affect the operation of the lighting system. Refer to «Checking Aftermarket Accessories»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__checking-aftermarket-accessories) .
  2. Inspect the easily accessible or visible system components for obvious damage or conditions which could cause the symptom.

Intermittent

Thoroughly inspect the wiring and connectors. An incomplete inspection of the wiring and connectors may result in misdiagnosis causing part replacement with the reappearance of the malfunction. If an intermittent malfunction exists, refer to Testing for Intermittent Conditions and Poor Connections .

Symptom List

Refer to a symptom diagnostic procedure from the following list in order to diagnose the symptom

  1. «Adaptive Forward Lighting Malfunction»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system)
  2. «Backup Lamps Malfunction»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system)
  3. «Courtesy Lamps Malfunction»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system)
  4. «Daytime Running Lamps Malfunction»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system)
  5. «Front Fog Lamps Malfunction»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system)
  6. «Rear Fog Lamps Malfunction»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system)
  7. «Hazard Lamps Malfunction»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system)
  8. «Headlamps Malfunction»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system)
  9. «Headlamp Leveling Malfunction (V-Series)»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system) or «Headlamp Leveling Malfunction (Base)»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system)
  10. «High Intensity Discharge Lamp Malfunction»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system)
  11. «Interior Accent Lighting Malfunction»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system)
  12. «Interior Backlighting Malfunction»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system)
  13. «Park, License, and/or Tail Lamps Malfunction (North America)»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system) or «Park, License, and/or Tail Lamps Malfunction (European)»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system)
  14. «Stop Lamps Malfunction»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system)
  15. «Trailer Lamps Malfunction»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system)
  16. «Turn Signal Lamps and/or Indicators Malfunction»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system)
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
AFL Headlamp Motor Control Circuit 1 - LeftB1461 02, 1B1461 00, 1B1461 00, 1B1461 39, B1461 54
AFL Headlamp Motor Control Circuit 2 - LeftB1461 02, 1B1461 00, 1B1461 00, 1B1461 39, B1461 54
AFL Headlamp Motor Control Circuit 3 - LeftB1461 02, 1B1461 00, 1B1461 00, 1B1461 39, B1461 54
AFL Headlamp Motor Control Circuit 4 - LeftB1461 02, 1B1461 00, 1B1461 00, 1B1461 39, B1461 54
AFL Headlamp Motor Control Circuit 1 - RightB1462 02, 1B1462 00, 1B1462 00, 1B1462 39, B1462 54
AFL Headlamp Motor Control Circuit 2 - RightB1462 02, 1B1462 00, 1B1462 00, 1B1462 39, B1462 54
AFL Headlamp Motor Control Circuit 3 - RightB1462 02, 1B1462 00, 1B1462 00, 1B1462 39, B1462 54
AFL Headlamp Motor Control Circuit 4 - RightB1462 02, 1B1462 00, 1B1462 00, 1B1462 39, B1462 54
1. Adaptive Forward Lighting Malfunction

Battery positive voltage is applied to the headlamp control module at all times. The headlamp control module has a normal operational voltage range of about 12.5-16 volts and is only fully functional with the ignition switch is in the RUN position and the headlamp switch in the AUTO position. The communications enable signal from the BCM wakes the headlamp control module microprocessor. The headlamp control module receives serial data messages from the engine control module (ECM), transmission control module (TCM), electronic brake control module (EBCM), and body control module (BCM) with regards to power mode, speed, steering angle, transmission gear selection, and headlamp switch status. The headlamp control module calculates the headlamp angle and sends commands to the left and right adaptive forward lighting system (AFL) headlamp actuators. The headlamp actuators drive the headlamps to the position commanded by the headlamp control module. The headlamp control module monitors the headlamp actuator motor control circuits for proper circuit continuity and for shorts to ground or voltage. If a malfunction is detected, a DTC will be stored in memory and the driver will be notified with a message displayed over the driver information center (DIC) located on the instrument panel cluster (IPC).

Diagnose any faults to the vehicle stability enhancement system (VSES) which contains the steering wheel position sensor before proceeding with this diagnostic procedure. A fault within the steering wheel position sensor will cause the adaptive forward lighting system to be inoperative.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

Ignition ON, with a scan tool, command the AFL Motor Control Left and Right while observing both headlamps. Both headlamps should operate to the Left and Right positions when commanded.

  1. Ignition OFF, disconnect the harness connector at the inoperative headlamp.
  2. Remove the AFS 15A fuse.
  3. Ignition OFF, scan tool OFF, test for 10 ohms -25K ohms between each control circuit terminal listed below and ground. AFL motor control terminal 1 AFL motor control terminal 2 AFL motor control terminal 3 AFL motor control terminal 4 If greater than the specified range, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the headlamp control module. If less than the specified range, test the control circuit for a short to ground. If the circuit tests normal, replace the headlamp control module.
  4. Install the AFS 15A fuse.
  5. Ignition ON, scan tool OFF, headlamps ON, verify that a test lamp does not illuminate between each control circuit terminal listed below and ground. AFL motor control terminal 1 AFL motor control terminal 2 AFL motor control terminal 3 AFL motor control terminal 4 If the test lamp illuminates, test the control circuit for a short to voltage. If the circuit tests normal, replace the headlamp control module.
  6. If all circuits test normal, replace the appropriate headlamp assembly.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Headlamp Assembly or Headlamp Bulb and/or Cornering, Sidemarker, Park, Turn Signal Bulb Replacement (TT6)»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system) or «Headlamp Assembly or Headlamp Bulb and/or Cornering, Sidemarker, Park, Turn Signal Bulb Replacement (TT7)»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system) or «Headlamp Assembly or Headlamp Bulb and/or Cornering, Sidemarker, Park, Turn Signal Bulb Replacement (TT8)»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system__headlamp-assembly-or-headlamp-bulb-andor) or «Headlamp Assembly or Headlamp Bulb and/or Cornering, Sidemarker, Park, Turn Signal Bulb Replacement (Without TT6/TT7/TT8/T84/T85)»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system)
  2. «Control Module References»(/cadillac/cts/ii-2007-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for headlamp control module replacement, setup, and programming
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Body Control Module (BCM) 4 Fuse B+B2545 00B2545 00
Backup Lamps ControlB2545 0011
Backup Lamp - Left Ground1
Backup Lamp - Right Ground1
1. Backup Lamps Malfunction

When the transmission is placed in the REVERSE position, the transmission control module (TCM) sends a serial data message to the body control module (BCM). The message indicates that the gear selector is in the REVERSE position. The BCM applies battery voltage to the backup lamps and inside rearview mirror. Once the driver moves the gear selector out of the REVERSE position, a message is sent by the TCM via serial data requesting the BCM to remove battery voltage from the backup lamp control circuit. The engine may need to be running for the backup lamps to function.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition OFF, disconnect the harness connector at the inoperative backup lamp.
  2. Ignition OFF, exterior lamps OFF, test for less than 5.0 ohms between the ground circuit terminal and ground. If greater than the specified range, test the ground circuit for an open/high resistance.
  3. Connect a test lamp between the control circuit terminal E and ground.
  4. Command the Backup Lamps ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states. If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the BCM. If the test lamp is always OFF, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, test the BCM 4 fuse B+ circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM.
  5. If all circuits test normal, test or replace the inoperative tail lamp.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Tail Lamp Replacement (Sedan, V-Series)»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system) or «Tail Lamp Replacement (Wagon)»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system)
  2. «Inside Rearview Mirror Replacement»(/cadillac/cts/ii-2007-2014/remont/mirrors/#mirror-system)
  3. «Control Module References»(/cadillac/cts/ii-2007-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM replacement, setup, and programming
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Body Control Module (BCM) 1 Fuse B+B1395 03B1395 03
Body Control Module (BCM) 2 Fuse B+55
Body Control Module (BCM) 3 Fuse B+B2615 00B2615 00
Dome Lamp Switch Signal222
Left Front Door Open Switch Signal333
Left Rear Door Open Switch Signal444
Right Front Door Open Switch Signal333
Right Rear Door Open Switch Signal444
Courtesy Lamp High Control - Driver DoorB2555 021B2555 01
Courtesy Lamp High Control - Passenger DoorB2555 021B2555 01
Courtesy Lamp Control11
Inadvertent Power Control555
Courtesy Lamp Low Control - Driver Door1
Courtesy Lamp Low Control - Passenger Door1
I/P Dimmer Switch Ground2
LH Vanity Mirror Courtesy Lamp Ground1
Trunk Courtesy Lamp Ground1
Overhead Console Courtesy Lamp Ground1
Rear Dome Lamp Ground1
RH Vanity Mirror Courtesy Lamp Ground1
1. Courtesy Lamps Malfunction 2. Dome Lamp Switch Malfunction 3. Door Open Switch Malfunction - Front 4. Door Open Switch Malfunction - Rear 5. Reading/Vanity Mirror Lamps Malfunction

The body control module (BCM) applies battery voltage to the courtesy lamps through the courtesy lamp supply voltage circuit. When any door is opened, the jam switch contacts close and the BCM receives a door-open input. If the BCM receives a door lock or unlock input or a rear hatch open input, the BCM will activate the courtesy lamp supply voltage circuit, providing battery voltage to all of the instrument panel (I/P) courtesy lamps, dome lamps, rearview mirror lamps, and rear compartment lamps. The BCM also provides a serial data message to the driver door module (DDM) and front passenger door module (PDM) to apply battery voltage to the door courtesy lamps. In the event that any of these lamps were to remain illuminated for more than 20 minutes with the ignition switch in the OFF position, the BCM will deactivate the inadvertent power courtesy lamp control circuit to prevent a total battery discharge condition.

Schematic Reference

  1. «Interior Lights Schematics»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system)
  2. «Door Lock/Indicator Schematics»(/cadillac/cts/ii-2007-2014/remont/door-locks-anti-theft-systems/#door-lock-system-door-handles)

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition ON, with a scan tool command the Courtesy Lamps ON and OFF. The front and rear overhead courtesy lamps should turn ON and OFF when commanded. If the overhead courtesy lamps do not illuminate when commanded, refer to Overhead Illuminated Entry Lamps Malfunction in «Circuit/System Testing»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system) .
  2. Ignition ON, observe the scan tool Ctsy. Lamp Actv. Reason parameter while turning the dome lamp switch ON and OFF. The reading should toggle between Off and Manual. If the reading does not change between the commanded states, refer to Dome Lamp Switch Malfunction in «Circuit/System Testing»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system) .
  3. Observe the scan tool Driver Door Open Switch parameter while opening and closing the driver door. The reading should toggle between Active and Inactive. If the reading does not change between the commanded states, refer to Door Open Switch Malfunction - Front in «Circuit/System Testing»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system) .
  4. Observe the scan tool Passenger Door Open Switch parameter while opening and closing the passenger door. The reading should toggle between Active and Inactive. If the reading does not change between the commanded states, refer to Door Open Switch Malfunction - Front in «Circuit/System Testing»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system) .
  5. Open each rear door one at a time and observe the courtesy lamps. The courtesy lamps should illuminated when each rear door is opened. If the courtesy lamps do not illuminate as each rear door is opened, refer to Door Open Switch Malfunction - Rear in «Circuit/System Testing»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system) .
  6. Turn the front and rear reading lamps ON and OFF. The lamps should turn ON and OFF when activated. If the reading lamps do not turn ON and OFF, refer to Reading Lamps Malfunction in «Circuit/System Testing»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system) .

Overhead Illuminated Entry Lamps Malfunction

  1. Ignition OFF, disconnect the X6 harness connector at the BCM.
  2. Ignition ON, verify that a test lamp illuminates between the BCM 3 fuse B+ circuit terminal 1 and ground. If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.
  3. Ignition OFF, reconnect the X6 harness connector at the BCM.
  4. Disconnect the harness connector at the inoperative courtesy/reading lamp assembly.
  5. Ignition OFF, scan tool OFF, doors CLOSED, interior lamps OFF, test for less than 5.0 ohms between the ground circuit terminal B and ground. If greater than the specified range, test the ground circuit for an open/high resistance.
  6. Connect a test lamp between the control circuit terminal A and ground.
  7. Command the Courtesy Lamps ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states. If the test lamp is always OFF, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM. If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the BCM.
  8. If all circuits test normal, replace the inoperative courtesy/reading lamp assembly.

Door Courtesy Lamp Malfunction - Front

  1. Ignition OFF, disconnect the harness connector at the appropriate front door courtesy lamp.
  2. Ignition ON, test for less than 20.0 ohms between the low control circuit terminal B and ground. If greater than the specified range, test the low reference circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the appropriate door control module.
  3. Connect a test lamp between the control circuit terminal A and the control circuit terminal B.
  4. Command the Puddle/courtesy Lamp ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states. If the test lamp is always ON, test the control circuit terminal A for a short to voltage. If the circuit tests normal, replace the appropriate door control module. If the test lamp is always OFF, test the control circuit terminal A for a short to ground or an open/high resistance. If the circuit tests normal, replace the appropriate door control module.
  5. If all circuits test normal, test or replace the appropriate door courtesy lamp.

Door Courtesy Lamp Malfunction - Rear

  1. Ignition OFF, disconnect the harness connector at the appropriate rear door courtesy lamp.
  2. Ignition OFF, verify that a test lamp illuminates between B+ and the ground circuit terminal B. If the test lamp does not illuminate, test the ground for an open/high resistance.
  3. Connect a test lamp between the control circuit terminal A and the ground circuit terminal B.
  4. Command the Courtesy Lamps ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states. If the test lamp is always OFF, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM. If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the BCM.
  5. If all circuits test normal, test or replace the appropriate rear door courtesy lamp.

Dome Lamp Switch Malfunction

  1. Ignition OFF, disconnect the harness connector at the I/P dimmer switch.
  2. Ignition OFF, scan tool OFF, interior lamps OFF, doors CLOSED, test for less than 1.0 ohm between the ground circuit terminal 7 and ground. If greater than the specified range, test the ground circuit for an open/high resistance.
  3. Ignition ON, verify the scan tool Ctsy. Lamp Actv. reason parameter is OFF. If not the specified value, test the signal circuit terminal 8 for a short to ground. If the circuit tests normal, replace the BCM.
  4. Install a 3A fused jumper wire between the signal circuit terminal 8 and ground. Verify the scan tool Ctsy. Lamp Actv. Reason parameter is Manual. If not the specified value, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the BCM.
  5. If all circuits test normal, test or replace the I/P dimmer switch.

Door Open Switch Malfunction - Front

  1. Ignition OFF, disconnect the harness connector at the inoperative door latch assembly.
  2. Ignition OFF, test for less than 10.0 ohms between the appropriate ground circuit terminal listed below and ground. Driver door latch ground circuit terminal 8 Passenger door latch ground circuit terminal 3 If greater than the specified range, test the ground circuit for an open/high resistance.
  3. Ignition ON, verify the scan tool Door Open Switch parameter is Inactive. If not the specified value, test the appropriate signal circuit terminal listed below for a short to ground. If the circuit tests normal, replace the appropriate door control module. Driver door open switch signal circuit terminal 7 Passenger door open switch signal circuit terminal 2
  4. Install a 3A fused jumper wire between the appropriate signal circuit terminal listed below and ground. Verify the scan tool Door Open Switch parameter is Active. Driver door open switch signal circuit terminal 7 Passenger door open switch signal circuit terminal 2 If not the specified value, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the appropriate door control module.
  5. If all circuits test normal, replace the inoperative door latch assembly.

Door Open Switch Malfunction - Rear

  1. Ignition OFF, disconnect the harness connector at the inoperative rear door latch assembly.
  2. Ignition OFF, interior lamps OFF, test for less than 10.0 ohms between the appropriate ground circuit terminal listed below and ground. Left rear door latch assembly ground circuit terminal 6 Right rear door latch assembly ground circuit terminal 3 If greater than the specified range, test the ground circuit for an open/high resistance.
  3. Ignition ON, verify that a test lamp illuminates between the appropriate door open switch signal circuit terminal listed below and ground. Left rear door open switch signal circuit terminal 5 Right rear door open switch signal circuit terminal 2 If the test lamp does not illuminate, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM.
  4. Install a 3A fused jumper wire between the appropriate signal circuit terminal listed below and ground. Verify the courtesy lamps illuminate and remain illuminated. Left rear door open switch signal circuit terminal 5 Right rear door open switch signal circuit terminal 2 If the courtesy lamps do not remain illuminated, test the signal circuit for a short to voltage. If the circuit tests normal, replace the BCM.
  5. If all circuits test normal, replace the inoperative rear door latch assembly.

Footwell Courtesy Lamp Malfunction

  1. Ignition OFF, disconnect the harness connector at the inoperative footwell courtesy lamp.
  2. Ignition OFF, scan tool OFF, test for less than 5.0 ohms between the ground circuit terminal B and ground. If greater than the specified range, test the ground circuit for an open/high resistance.
  3. Connect a test lamp between the control circuit terminal A and ground.
  4. Command the Courtesy Lamps ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states. If the test lamp does not illuminate, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM.
  5. Remove the BCM 2 fuse and verify the test lamp turns OFF. If the test lamp remains illuminated, test the control circuit for a short to voltage. If the circuit tests normal, replace the BCM.
  6. If all circuits test normal, replace the inoperative footwell courtesy lamp.

I/P Compartment Lamp Malfunction

  1. Ignition OFF, disconnect the harness connector at the I/P compartment lamp.
  2. Open the I/P compartment.
  3. Ignition OFF, verify that a test lamp illuminates between B+ and the ground circuit terminal A. If the test lamp does not illuminate, test the ground circuit for an open/high resistance. If the circuit tests normal, replace the I/P compartment lamp switch.
  4. Ignition OFF, verify that a test lamp illuminates between the control circuit terminal B and ground. If the test lamp does not illuminate, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM.
  5. Remove the BCM 2 fuse and verify the test lamp turns OFF. If the test lamp remains illuminated, test the control circuit for a short to voltage. If the circuit tests normal, replace the BCM.
  6. If all circuits test normal, replace the I/P compartment lamp.

Reading Lamps Malfunction

  1. Ignition OFF, disconnect the X3 harness connector at the BCM.
  2. Ignition ON, verify that a test lamp illuminates between the BCM 2 fuse B+ circuit terminal 2 and ground. If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.
  3. Ignition OFF, reconnect the X3 harness connector at the BCM.
  4. Disconnect the harness connector at the inoperative courtesy/reading lamp assembly.
  5. Ignition OFF, scan tool OFF, doors CLOSED, interior lamps OFF, test for less than 5.0 ohms between the ground circuit terminal B and ground. If greater than the specified range, test the ground circuit for an open/high resistance.
  6. Ignition OFF, verify that a test lamp illuminates between the control circuit terminal C and ground. If the test lamp does not illuminate, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM.
  7. Remove the BCM 2 fuse and verify the test lamp turns OFF. If the test lamp remains illuminated, test the control circuit for a short to voltage. If the circuit tests normal, replace the BCM.
  8. If all circuits test normal, replace the inoperative courtesy/reading lamp assembly.

Rear Compartment Courtesy Lamp Malfunction

  1. Ignition OFF, disconnect the harness connector at the rear compartment courtesy lamp.
  2. Open the trunk.
  3. Ignition OFF, verify that a test lamp illuminates between B+ and the ground circuit terminal B. If the test lamp does not illuminate, test the ground circuit for short to voltage or an open/high resistance. If the circuit tests normal, replace the rear compartment release switch.
  4. Ignition OFF, verify that a test lamp illuminates between the control circuit terminal C and ground. If the test lamp does not illuminate, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM.
  5. Remove the BCM 2 fuse and verify the test lamp turns OFF. If the test lamp remains illuminated, test the control circuit for a short to voltage. If the circuit tests normal, replace the BCM.
  6. If all circuits test normal, replace the rear compartment courtesy lamp.

Vanity Mirror Lamps Malfunction

  1. Ignition OFF, disconnect the harness connector at the inoperative vanity mirror.
  2. Ignition OFF, scan tool OFF, doors CLOSED, interior lamps OFF, test for less than 5.0 ohms between the ground circuit terminal B and ground. If greater than the specified range, test the ground circuit for an open/high resistance.
  3. Ignition ON, verify that a test lamp illuminates between the control circuit terminal A and ground. If the test lamp does not illuminate, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM.
  4. Remove the BCM 2 fuse and verify the test lamp turns OFF. If the test lamp remains illuminated, test the control circuit for a short to voltage. If the circuit tests normal, replace the BCM.
  5. If all circuits test normal, replace the inoperative vanity mirror.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Sunshade Illuminated Mirror Lamp Bulb Replacement»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system)
  2. «Overhead Console Reading Lamp and Bulb Replacement»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system)
  3. «Instrument Panel Courtesy Lamp Bulb Replacement»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system)
  4. «Door Courtesy Lamp and Reflector Replacement»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system)
  5. «Door Lamp Replacement»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system)
  6. «Instrument Panel Lamp Dimmer Switch Replacement»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system)
  7. «Rear Compartment Lid Release Switch Replacement (Sedan)»(/cadillac/cts/ii-2007-2014/remont/door-locks-anti-theft-systems/#door-lock-system-door-handles)
  8. «Sunshade Replacement»(/cadillac/cts/ii-2007-2014/remont/exteriorinterior-trim/#interior-trim-system-and-paneling)
  9. «Front Side Door Latch Replacement (Sedan/Wagon)»(/cadillac/cts/ii-2007-2014/remont/door-locks-anti-theft-systems/#door-lock-system-door-handles)
  10. «Rear Side Door Latch Replacement»(/cadillac/cts/ii-2007-2014/remont/door-locks-anti-theft-systems/#door-lock-system-door-handles)
  11. «Control Module References»(/cadillac/cts/ii-2007-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM, DDM, or PDM replacement, setup, and programming
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Ambient Light Sensor SignalB2645 03B2645 07B2645 07
Left Sun Load Sensor SignalB0183 06B0183 06B0183 06
Right Sun Load Sensor SignalB0188 06B0188 06B0188 06
Daytime Running Lamp - Left Control222
Daytime Running Lamp - Right Control222
Headlamp - Left Front Low Beam Control111
Headlamp - Right Front Low Beam Control111
Ambient Light Sensor Low ReferenceB2645 07B0183 06, B0188 06
Daytime Running Lamp - Left Ground2
Daytime Running Lamp - Right Ground2
Headlamp - Left Front Ground1
Headlamp - Right Front Ground1
1. Headlamps Malfunction 2. Daytime Running Lamps Malfunction

Daytime Running Lamps without HID

The ambient light sensor is used to monitor outside lighting conditions. The ambient light sensor provides a voltage signal that will vary between 0.2 and 4.9 volts depending on outside lighting conditions. The HVAC control module provides a low reference ground and 5-volt reference signals to the ambient light sensor. The body control module (BCM) monitors the ambient light sensor signal circuit to determine if outside lighting conditions are correct for either daytime running lights (DRL) or automatic lamp control (ALC) when the headlamp switch is in the AUTO position. In daylight conditions the BCM will command the low beam headlamps ON. Any function or condition that turns on the headlamps will cancel DRL operation.

Daytime Running Lamps with HID

The ambient light sensor is used to monitor outside lighting conditions. The ambient light sensor provides a voltage signal that will vary between 0.2 and 4.9 volts depending on outside lighting conditions. The HVAC control module provides a low reference ground and 5-volt reference signals to the ambient light sensor. The body control module (BCM) monitors the ambient light sensor signal circuit to determine if outside lighting conditions are correct for either daytime running lights (DRL) or automatic lamp control (ALC) when the headlamp switch is in the AUTO position. In daylight conditions, the BCM will command the DRLs ON by applying ground to the left and right DRL relays via separate left and right DRL relay control circuits. When the BCM applies ground to the relay control circuits, the left and right DRL relay coils energize causing both relay switch contacts to close. With the left and right DRL relay switch contacts closed, battery voltage flows through the left and right DRL fuses to the left and right DRL lamps. Any function or condition that turns on the headlamps will cancel DRL operation.

Note. This diagnostic procedure assumes that the low beam headlamps are operating within specifications. If the low beam headlamps are inoperative, diagnose the low beam headlamp malfunction before proceeding with the following diagnostic. Refer to Headlamps Malfunction .

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

Daytime Running Lamps Malfunction without HID

  1. Ignition OFF, disconnect the harness connector at the sunload sensor assembly.
  2. Ignition OFF, scan tool OFF, doors CLOSED, test for less than 10.0 ohms between the low reference circuit terminal C and ground. If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the HVAC control module.
  3. Ignition ON, verify the scan tool Ambient Light Sensor parameter is greater than 4.65 volts. If less than the specified range, test the signal circuit terminal D for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM.
  4. Verify the scan tool Ambient Light Sensor parameter is less than 0.196 volts. If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the BCM.
  5. If all circuits test normal, replace the sunload sensor assembly.

Daytime Running Lamps Malfunction with HID

  1. Ignition OFF, disconnect the appropriate DRL relay.
  2. Ignition ON, verify that a test lamp does not illuminate between the control circuit terminal 87 and ground. If the test lamp illuminates, test the control circuit for a short to voltage.
  3. Verify that a test lamp illuminates between the B+ circuit terminal 30 and ground. If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance. If the circuit tests normal and the B+ circuit fuse is open, test the control circuit terminal 87 for a short to ground. If the circuit tests normal, test or replace the appropriate DRL relay.
  4. Verify that a test lamp illuminates between the B+ circuit terminal 85 and ground. If the test lamp does not illuminate, test the B+ circuit for an open/high resistance.
  5. Ignition OFF, disconnect the harness connector at the inoperative DRL.
  6. Ignition OFF, exterior lamps OFF, test for less than 5.0 ohms between the ground circuit terminal B and ground. If greater than the specified range, test the ground circuit for an open/high resistance.
  7. Connect the harness connector at the inoperative DRL.
  8. Connect a 5A fused jumper wire between the B+ circuit terminal 30 and the control circuit terminal 87. Verify the appropriate DRL is activated. If the DRL does not activate, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the inoperative DRL.
  9. Connect a test lamp between the B+ circuit terminal 85 and the relay control circuit terminal 86.
  10. Place a bright incandescent light directly over the ambient light sensor.
  11. Engine ON, headlamp switch in AUTO position, vehicle in DRIVE, verify the test lamp illuminates when the AUTO headlamps turn off automatically. If the test lamp is always OFF, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the BCM. If the test lamp is always ON, test the control circuit for a short to ground. If the circuit tests normal, replace the BCM.
  12. If all circuits test normal, test or replace the DRL relay.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Headlamp Automatic Control Ambient Light Sensor Replacement»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system)
  2. «Headlamp Assembly or Headlamp Bulb and/or Cornering, Sidemarker, Park, Turn Signal Bulb Replacement (TT6)»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system) or «Headlamp Assembly or Headlamp Bulb and/or Cornering, Sidemarker, Park, Turn Signal Bulb Replacement (TT7)»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system) or «Headlamp Assembly or Headlamp Bulb and/or Cornering, Sidemarker, Park, Turn Signal Bulb Replacement (TT8)»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system__headlamp-assembly-or-headlamp-bulb-andor) or «Headlamp Assembly or Headlamp Bulb and/or Cornering, Sidemarker, Park, Turn Signal Bulb Replacement (Without TT6/TT7/TT8/T84/T85)»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system)
  3. «Control Module References»(/cadillac/cts/ii-2007-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM or HVAC control module replacement, setup, and programming
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Front Fog Lamp Switch Signal222
Front Fog Lamp Relay Control11B2530 00
Front Fog Lamp Control111
Fog Lamp - LF Ground1
Fog Lamp - RF Ground1
Fog Lamp Switch Ground2
1. Front Fog Lamps Malfunction 2. Front Fog Lamp Switch Malfunction

The front fog lamp relay is supplied with battery voltage at all times. The front fog lamp switch signal circuit is grounded momentarily by pressing the front fog lamp switch. The body control module (BCM) energizes the front fog lamp relay by applying ground to the front fog lamp relay control circuit. When the front fog lamp relay is energized, the relay switch contacts close and battery voltage is applied through the FRT FOG fuse to the front fog lamp supply voltage circuit which illuminates the front fog lamps.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition ON, observe the scan tool Front Fog Lamp Switch parameter while activating the front fog lamp switch. The parameter should change between Active and Inactive. If the parameter does not change between the commanded states, refer to Front Fog Lamp Switch Malfunction in «Circuit/System Testing»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system) .
  2. Turn the front fog lamps ON and OFF with the front fog lamps switch. The front fog lamps should turn ON and OFF as selected. If the front fog lamps do not change between the selected states, refer to Front Fog Lamps Malfunction in «Circuit/System Testing»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system) .
  3. Command the Display Test ON and OFF with a scan tool. The front fog lamps indicator should turn ON and OFF when changing between the commanded states. If the front fog lamps indicator illuminates during the test, replace the BCM. If the front fog lamps indicator does not illuminate during the test or remains illuminated at all times, replace the instrument cluster.

Front Fog Lamp Switch Malfunction

  1. Ignition OFF, disconnect the X1 harness connector at the turn signal/multifunction switch.
  2. Ignition OFF, verify that a test lamp illuminates between B+ and the ground circuit terminal 10. If the test lamp does not illuminate, test the ground circuit for an open/high resistance.
  3. Ignition ON, verify the scan tool Front Fog Lamp Switch parameter is Inactive. If not the specified value, test the signal circuit terminal 7 for a short to ground. If the circuit tests normal, replace the BCM.
  4. Install a 3 A fused jumper wire between the signal circuit terminal 7 and the ground circuit terminal 10. Verify the scan tool Front Fog Lamp Switch parameter is Active. If not the specified value, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the BCM.
  5. If all circuits test normal, test or replace the turn signal/multifunction switch.

Front Fog Lamps Malfunction

  1. Ignition OFF, disconnect the front fog lamp relay.
  2. Ignition ON, verify that a test lamp does not illuminate between the control circuit terminal 87 and ground. If the test lamp illuminates, test the control circuit for a short to voltage.
  3. Verify that a test lamp illuminates between the B+ circuit terminal 30 and ground. If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.
  4. Verify that a test lamp illuminates between the B+ circuit terminal 85 and ground. If the test lamp does not illuminate, test the B+ circuit for an open/high resistance.
  5. Disconnect the harness connector at the inoperative front fog lamp.
  6. Ignition OFF, test for less than 5 ohms between the ground circuit terminal B and ground. If greater than the specified range, test the ground circuit for an open/high resistance.
  7. Connect the harness connector at the inoperative front fog lamp.
  8. Connect a 15 A fused jumper wire between the B+ circuit terminal 30 and the control circuit terminal 87. Verify the front fog lamps illuminate. If the front fog lamps do not illuminate, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the inoperative front fog lamp.
  9. Connect a test lamp between the B+ circuit terminal 85 and the control circuit terminal 86.
  10. Command the Front Fog Lamps ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states. If the test lamp is always ON, test the control circuit for a short to ground. If the circuit tests normal, replace the BCM. If the test lamp is always OFF, test the control circuit for a short to voltage or open/high resistance. If the circuit tests normal, replace the BCM.
  11. If all circuits test normal, test or replace the front fog lamp relay.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Front Fog Lamp Replacement (Sedan)»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system) or «Front Fog Lamp Replacement (V-Series)»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system)
  2. «Relay Replacement (Attached to Wire Harness)»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-repair-instructions) or «Relay Replacement (Within an Electrical Center)»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-repair-instructions)
  3. «Turn Signal Multifunction Switch Replacement»(/cadillac/cts/ii-2007-2014/remont/steering-column-switches/#steering-wheel-steering-column)
  4. «Underhood Electrical Center or Junction Block Replacement»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-repair-instructions)
  5. «Control Module References»(/cadillac/cts/ii-2007-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM or IPC replacement, setup, and programming
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Rear Fog Lamp Switch SignalB3588 0222
Rear Fog Lamp Relay ControlB2540 02B2540 05B2540 05
Rear Fog Lamp Control111
Fog Lamp - LR Ground1
Fog Lamp - RR Ground1
Rear Fog Lamp Switch Ground2
1. Rear Fog Lamps Malfunction 2. Rear Fog Lamp Switch Malfunction

The rear fog lamp relay is supplied with battery voltage at all times from the REAR FOG fuse located in the rear fuse block. The rear fog lamp switch signal circuit is grounded momentarily by pressing the rear fog lamp switch. The body control module (BCM) energizes the rear fog lamp relay by applying ground to the rear fog lamp relay control circuit. When the rear fog lamp relay is energized, the relay switch contacts close and battery voltage is applied through the REAR FOG fuse to the rear fog lamp supply voltage circuit which illuminates the rear fog lamps.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition ON, observe the scan tool Rear Fog Lamp Switch parameter while turning the rear fog lamp switch ON and OFF. The parameter should change between Active and Inactive. If the parameter does not change between the selected states, refer to Rear Fog Lamp Switch Malfunction in «Circuit/System Testing»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system) .
  2. Turn the rear fog lamps ON and OFF with the rear fog lamps switch. The rear fog lamps should turn ON and OFF as selected. If the rear fog lamps do not change between the selected states, refer to Rear Fog Lamps Malfunction in «Circuit/System Testing»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system) .
  3. Command the Display Test ON and OFF with a scan tool. The rear fog lamps indicator should turn ON and OFF when changing between the commanded states. If the rear fog lamps indicator illuminates during the test, replace the BCM. If the rear fog lamps indicator does not illuminate during the test or remains illuminated at all times, replace the instrument cluster.

Rear Fog Lamp Switch Malfunction

  1. Ignition OFF, disconnect the X1 harness connector at the turn signal/multifunction switch.
  2. Ignition OFF, verify that a test lamp illuminates between B+ and the ground circuit terminal 10. If the test lamp does not illuminate, test the ground circuit for an open/high resistance.
  3. Ignition ON, verify the scan tool Rear Fog Lamp Switch parameter is Inactive. If not the specified value, test the signal circuit terminal 8 for a short to ground. If the circuit tests normal, replace the BCM.
  4. Install a 3 A fused jumper wire between the signal circuit terminal 8 and the ground circuit terminal 10. Verify the scan tool Rear Fog Lamp Switch parameter is Active. If not the specified value, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the BCM.
  5. If all circuits test normal, test or replace the turn signal/multifunction switch.

Rear Fog Lamps Malfunction

  1. Ignition OFF, disconnect the rear fog lamp relay.
  2. Ignition ON, verify that a test lamp does not illuminate between the control circuit terminal 87 and ground. If the test lamp illuminates, test the control circuit for a short to voltage.
  3. Verify that a test lamp illuminates between the B+ circuit terminal 30 and ground. If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance. If the circuit tests normal and the B+ circuit fuse is open, test the control circuit terminal 87 for a short to ground. If the circuit tests normal, test or replace the rear fog lamp relay.
  4. Verify that a test lamp illuminates between the B+ circuit terminal 85 and ground. If the test lamp does not illuminate, test the B+ circuit for an open/high resistance.
  5. Disconnect the harness connector at the inoperative rear fog lamp.
  6. Ignition OFF, test for less than 5 ohms between the ground circuit terminal B and ground. If greater than the specified range, test the ground circuit for an open/high resistance.
  7. Connect the harness connector at the inoperative rear fog lamp.
  8. Connect a 10 A fused jumper wire between the B+ circuit terminal 30 and the control circuit terminal 87. Verify the rear fog lamps illuminate. If the rear fog lamps do not illuminate, test the control circuit for an open/high resistance. If the circuit tests normal, replace the inoperative rear fog lamp.
  9. Connect a test lamp between the B+ circuit terminal 85 and the control circuit terminal 86.
  10. Command the Rear Fog Lamps ON and OFF with the rear fog lamp switch. The test lamp should turn ON and OFF when changing between the commanded states. If the test lamp is always ON, test the control circuit for a short to ground. If the circuit tests normal, replace the BCM. If the test lamp is always OFF, test the control circuit for a short to voltage or open/high resistance. If the circuit tests normal, replace the BCM.
  11. If all circuits test normal, test or replace the rear fog lamp relay.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Rear Fog Lamp Replacement (T79)»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system)
  2. «Relay Replacement (Attached to Wire Harness)»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-repair-instructions) or «Relay Replacement (Within an Electrical Center)»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-repair-instructions)
  3. «Turn Signal Multifunction Switch Replacement»(/cadillac/cts/ii-2007-2014/remont/steering-column-switches/#steering-wheel-steering-column)
  4. «Control Module References»(/cadillac/cts/ii-2007-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM or IPC replacement, setup, and programming
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Hazard Switch Signal111
Hazard Switch Ground1
1. Hazard Lamps Malfunction

The hazard flashers may be activated in any power mode. The hazard switch is located on the radio/HVAC control panel. The hazard switch signal circuit is momentarily grounded when the hazard switch is pressed. The body control module (BCM) supplies battery voltage to all four turn signal lamps in an ON and OFF duty cycle. When the hazard switch is activated, the BCM sends a serial data message to the instrument panel cluster (IPC) requesting both turn signal indicators to be cycled ON and OFF.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition ON, observe the scan tool Hazard Lamp Switch parameter while pressing and releasing the hazard switch twice. The parameter should change between Active and Inactive. If the parameter does not change between the selected states, refer to «Circuit/System Testing»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system) .
  2. Ignition ON, command the Display Test ON and OFF with a scan tool. Both turn signal indicators should turn ON and OFF when changing between the commanded states. If both turn signal indicators are always ON or OFF, replace the instrument cluster.
  1. Ignition OFF, disconnect the harness connector at the hazard switch.
  2. Ignition OFF, verify that a test lamp illuminates between B+ and the ground circuit terminal 16. If the test lamp does not illuminate, test the ground circuit for an open/high resistance.
  3. Ignition ON, verify the scan tool Hazard Lamp Switch parameter is Inactive. If not the specified value, test the signal circuit terminal 15 for a short to ground. If the circuit tests normal, replace the BCM.
  4. Install a 3 A fused jumper wire between the signal circuit terminal 15 and ground. Verify the scan tool Hazard Lamp Switch parameter is Active. If not the specified value, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the BCM.
  5. If all circuits test normal, replace the radio/HVAC control panel.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Radio Control Assembly Replacement (with Navigation Display)»(/cadillac/cts/ii-2007-2014/remont/entertainment-systems/#cellular-system-entertainment-system-and-navigation-system) or «Radio Control Assembly Replacement (without Navigation Display)»(/cadillac/cts/ii-2007-2014/remont/entertainment-systems/#cellular-system-entertainment-system-and-navigation-system)
  2. «Control Module References»(/cadillac/cts/ii-2007-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM or IPC replacement, setup, and programming
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Headlamp Switch Headlamps ON SignalB257A 0011
Headlamp Switch Headlamps OFF SignalB257A 0011
Headlamp Low Beam Relay Control22B2575 00
LF Low Beam Headlamp Control222
RF Low Beam Headlamp Control222
LF Headlamp Ground2
RF Headlamp Ground2
Turn Signal/Multifunction Switch Ground1
1. Headlamp Switch Malfunction 2. Headlamps Malfunction - Low Beam

With the headlamp switch in the ON position, the headlamp switch headlamp ON signal circuit is grounded through the turn signal/multifunction switch. In response to this input, the body control module (BCM) provides ground to the headlamp low beam relay control circuit. The position of the headlamp dimmer switch determines which relay coil is supplied with ground. The BCM supplies ground to the relay coil circuits, if the headlamps are necessary. The underhood fuse block supplies battery positive voltage to the relay coil and switch circuits. The low beam headlamps operate when the BCM grounds the relay coil control circuit to the relay coil of the low beam headlamp relay. This energizes the low beam relay causing the switch contacts to close. With the switch contacts closed, battery voltage is applied to the LT LO and RT LO beam fuses through to the left and right low beam headlamps.

The following symptoms are noticeable signs of bulb failure

  1. Flickering light, caused in the early stages of bulb failure.
  2. Lights go out, caused when the ballast detects excessive, repetitive bulb re-strike.
  3. Color change-The lamp may change to a dim pink glow.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

WARNINGThe high intensity discharge system produces high voltage and current. To reduce the risk of severe shocks and burns: Never open the high intensity discharge system ballast or the arc tube assembly starter. Never probe between the high intensity discharge system ballast output connector and the arc tube assembly.
  1. Ignition OFF, disconnect the LO beam relay.
  2. Ignition ON, verify that a test lamp does not illuminate between the control circuit terminal 87 and ground. If the test lamp illuminates, test the control circuit for a short to voltage.
  3. Verify that a test lamp illuminates between the B+ circuit terminal 85 and ground. If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.
  4. Verify that a test lamp illuminates between the B+ circuit terminal 30 and ground. If the test lamp does not illuminate, test the B+ circuit for an open/high resistance.
  5. Disconnect the harness connector at the appropriate headlamp.
  6. Test for less than 5 ohms between the headlamp ground circuit terminal 2 and ground If greater than the specified range, test the ground circuit for an open/high resistance.
  7. Connect the harness connector at the headlamp.
  8. Connect a 20 A fused jumper wire between the B+ circuit terminal 30 and the control circuit terminal 87. Verify the headlamp is activated. If the headlamp does not activate and the jumper wire fuse is good, test the control circuit for an open/high resistance. If the circuit tests normal, test or replace the headlamp. If the headlamp does not activate and the jumper wire fuse is open, test the control circuit for a short to ground. If the circuit tests normal, test or replace the headlamp.
  9. Connect a test lamp between the B+ circuit terminal 85 and the control circuit terminal 86.
  10. Command the Low Beams ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states. If the test lamp is always ON, test the control circuit for a short to ground. If the circuit tests normal, replace the BCM. If the test lamp is always OFF, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the BCM.
  11. If all circuits test normal, test or replace the LO beam relay.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Headlamp Assembly or Headlamp Bulb and/or Cornering, Sidemarker, Park, Turn Signal Bulb Replacement (TT6)»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system) or «Headlamp Assembly or Headlamp Bulb and/or Cornering, Sidemarker, Park, Turn Signal Bulb Replacement (TT7)»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system) or «Headlamp Assembly or Headlamp Bulb and/or Cornering, Sidemarker, Park, Turn Signal Bulb Replacement (TT8)»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system__headlamp-assembly-or-headlamp-bulb-andor) or «Headlamp Assembly or Headlamp Bulb and/or Cornering, Sidemarker, Park, Turn Signal Bulb Replacement (Without TT6/TT7/TT8/T84/T85)»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system)
  2. «Headlamp Ballast Replacement (Sedan)»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system) or «Headlamp Ballast Replacement (European)»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system__headlamp-ballast-replacement-european)
  3. «Headlamp Capsule Replacement»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system)
  4. «Relay Replacement (Attached to Wire Harness)»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-repair-instructions) or «Relay Replacement (Within an Electrical Center)»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-repair-instructions)
  5. «Control Module References»(/cadillac/cts/ii-2007-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM or IPC replacement, setup and programming
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Flash to Pass Switch Signal111
Headlamp Switch High Beam Signal111
Headlamp Switch Headlamps ON SignalB257A 0011
Headlamp Switch Headlamps OFF SignalB257A 0011
Headlamp High Beam Relay Control33B2580 00
Headlamp Low Beam Relay Control22B2575 00
LF High Beam Headlamp Control333
LF Low Beam Headlamp Control222
RF High Beam Headlamp Control333
RF Low Beam Headlamp Control222
LF Headlamp Ground2
RF Headlamp Ground2
Turn Signal/Multifunction Switch Ground1
1. Headlamp Switch Malfunction 2. Headlamps Malfunction - Low Beam 3. Headlamps Malfunction - High Beam

With the headlamp switch in the ON position, the headlamp switch headlamp ON signal circuit is grounded through the turn signal/multifunction switch. In response to this input, the body control module (BCM) provides ground to either the headlamp low beam relay control circuit or the headlamp high beam relay control circuit. The position of the headlamp dimmer switch determines which relay coil is supplied with ground. The BCM supplies ground to the relay coil circuits, if the headlamps are necessary. The underhood fuse block supplies battery positive voltage to the relay coil and switch circuits. The low beam headlamps operate when the BCM grounds the relay coil control circuit to the relay coil of the low beam headlamp relay. This energizes the low beam relay causing the switch contacts to close. With the switch contacts closed, battery voltage is applied to the LT LO and RT LO beam fuses through to the left and right low beam headlamps. When the headlamp high beam relay coil is energized, current flows through the LT HI BEAM and the RT HI BEAM fuses to the high beam headlamps. With the headlamp dimmer switch in the high beam position the BCM sends a message via serial data to the instrument panel cluster (IPC) requesting the IPC to illuminate the high beam indicator.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition ON, observe the scan tool Headlamp Switch parameter while turning the headlamp switch ON and OFF. The reading should change between Active and Inactive. If the reading does not change between the specified values, refer to Turn Signal/Multifunction Switch Malfunction in «Circuit/System Testing»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system) .
  2. Observe the scan tool Flash to Pass Switch parameter while applying and releasing the turn signal/multifunction switch. The reading should toggle between Active and Inactive. If the reading does not change between the specified values, refer to Turn Signal/Multifunction Switch Malfunction in «Circuit/System Testing»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system) .
  3. Observe the scan tool High Beam Select switch parameter while applying and releasing the high beam select switch. The reading should toggle between Active and Inactive. If the reading does not change between the commanded states, refer to Turn Signal/Multifunction Switch Malfunction in «Circuit/System Testing»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system) .
  4. Observe the scan tool Auto Hdlp. Disable Sw. parameter while applying and releasing the automatic lamp control disable switch. The reading should toggle between Active and Inactive. If the reading does not change between the commanded states, refer to Turn Signal/Multifunction Switch Malfunction in «Circuit/System Testing»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system) .
  5. Command the Low Beams ON and OFF with a scan tool. The low beam headlamps should turn ON and OFF when commanded. If the low beam headlamps do not turn ON and OFF when commanded, refer to Headlamps Malfunction - Low Beam in «Circuit/System Testing»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system) .
  6. Command the High Beams ON and OFF with a scan tool. The high beam headlamps should turn ON and OFF when commanded. If the high beam headlamps do not turn ON and OFF when commanded, refer to Headlamps Malfunction - High Beam in «Circuit/System Testing»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system) .
  7. Command the Display Test ON and OFF with a scan tool. The lights on indicator and high beam indicator should turn ON and OFF when changing between the commanded states. If the lights on indicator and high beam indicator illuminate during the test, replace the BCM. If the lights on indicator and high beam indicator do not illuminate during the test or remain illuminated at all times, replace the instrument cluster.
WARNINGThe high intensity discharge system produces high voltage and current. To reduce the risk of severe shocks and burns: Never open the high intensity discharge system ballast or the arc tube assembly starter. Never probe between the high intensity discharge system ballast output connector and the arc tube assembly.

Turn Signal/Multifunction Switch Malfunction

  1. Ignition OFF, disconnect the X1 and X2 harness connectors at the turn signal/multifunction switch.
  2. Ignition OFF, verify that a test lamp illuminates between B+ and the ground circuit terminal 9. If the test lamp does not illuminate, test the ground circuit for an open/high resistance.
  3. Ignition OFF, verify that a test lamp illuminates between B+ and the ground circuit terminal 8. If the test lamp does not illuminate, test the ground circuit for an open/high resistance.
  4. Ignition OFF, verify that a test lamp illuminates between B+ and the ground circuit terminal 1. If the test lamp does not illuminate, test the ground circuit for an open/high resistance.
  5. Ignition ON, verify the scan tool Headlamp Switch parameter is Inactive. If not the specified value, test the signal circuit terminal 5 for short to ground. If the circuit tests normal, replace the BCM.
  6. Verify the scan tool Auto Hdlp. Disable Sw. parameter is Inactive. If not the specified value, test the signal circuit terminal 4 for short to ground. If the circuit tests normal, replace the BCM.
  7. Verify the scan tool Flash to Pass Switch parameter is Inactive. If not the specified value, test the signal circuit terminal 10 for a short to ground. If the circuit tests normal, replace the BCM.
  8. Verify the scan tool High Beam Select switch parameter is Inactive. If not the specified value, test the signal circuit terminal 7 for a short to ground. If the circuit tests normal, replace the BCM.
  9. Install a 3 A fused jumper wire between the signal circuit terminal 5 and ground. Verify the scan tool Headlamp Switch parameter is Active. If not the specified value, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the BCM.
  10. Install a 3 A fused jumper wire between the signal circuit terminal 4 and ground. Verify the scan tool Auto Hdlp. Disable Sw. parameter is Active. If not the specified value, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the BCM.
  11. Install a 3 A fused jumper wire between the signal circuit terminal 10 and ground. Verify the scan tool Flash to Pass Switch parameter is Active. If not the specified value, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the BCM.
  12. Install a 3 A fused jumper wire between the signal circuit terminal 7 and ground. Verify the scan tool High Beam Select switch parameter is Active. If not the specified value, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the BCM.
  13. If all circuits test normal, test or replace the turn signal/multifunction switch.

Headlamps Malfunction - Low Beam

  1. Ignition OFF, disconnect the DRL relay.
  2. Ignition ON, verify that a test lamp does not illuminate between the control circuit terminal 87 and ground. If the test lamp illuminates, test the control circuit for a short to voltage.
  3. Verify that a test lamp illuminates between the B+ circuit terminal 85 and ground. If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.
  4. Verify that a test lamp illuminates between the B+ circuit terminal 30 and ground. If the test lamp does not illuminate, test the B+ circuit for an open/high resistance.
  5. Disconnect the harness connector at the appropriate headlamp - low beam.
  6. Test for less than 5 ohms between the headlamp - low beam ground circuit terminal B and ground: If greater than the specified range, test the ground circuit for an open/high resistance.
  7. Connect the harness connector at the headlamp - low beam.
  8. Connect a 10 A fused jumper wire between the B+ circuit terminal 30 and the control circuit terminal 87. Verify the headlamp - low beam is activated. If the headlamp - low beam does not activate and the jumper wire fuse is good, test the control circuit for an open/high resistance. If the circuit tests normal, test or replace the headlamp - low beam. If the headlamp - low beam does not activate and the jumper wire fuse is open, test the control circuit for a short to ground. If the circuit tests normal, test or replace the headlamp - low beam.
  9. Connect a test lamp between the B+ circuit terminal 85 and the control circuit terminal 86.
  10. Command the Low Beams ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states. If the test lamp is always ON, test the control circuit for a short to ground. If the circuit tests normal, replace the BCM. If the test lamp is always OFF, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the BCM.
  11. If all circuits test normal, test or replace the DRL relay.

Headlamps Malfunction - High Beam

  1. Ignition OFF, disconnect the HI beam relay.
  2. Ignition ON, verify that a test lamp does not illuminate between the control circuit terminal 87 and ground. If the test lamp illuminates, test the control circuit for a short to voltage.
  3. Verify that a test lamp illuminates between the B+ circuit terminal 85 and ground. If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.
  4. Verify that a test lamp illuminates between the B+ circuit terminal 30 and ground. If the test lamp does not illuminate, test the B+ circuit for an open/high resistance.
  5. Disconnect the harness connector at the appropriate headlamp - high beam.
  6. Test for less than 5 ohms between the headlamp - high beam ground circuit terminal listed below and ground: With TT6, TT7 and TT8 - Terminal 2 Without TT6, TT7 and TT8 - Terminal B If greater than the specified range, test the ground circuit for an open/high resistance.
  7. Connect the harness connector at the headlamp - high beam.
  8. Connect a 10 A fused jumper wire between the B+ circuit terminal 30 and the control circuit terminal 87. Verify the headlamp - high beam is activated. If the headlamp - high beam does not activate and the jumper wire fuse is good, test the control circuit for an open/high resistance. If the circuit tests normal, test or replace the headlamp - high beam. If the headlamp - high beam does not activate and the jumper wire fuse is open, test the control circuit for a short to ground. If the circuit tests normal, test or replace the headlamp - high beam.
  9. Connect a test lamp between the B+ circuit terminal 85 and the control circuit terminal 86.
  10. Command the High Beams ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states. If the test lamp is always ON, test the control circuit for a short to ground. If the circuit tests normal, replace the BCM. If the test lamp is always OFF, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the BCM.
  11. If all circuits test normal, test or replace the HI beam relay.

Headlamps Malfunction - High Intensity Discharge Headlamps

  1. Ignition OFF, disconnect the LO beam relay.
  2. Ignition ON, verify that a test lamp does not illuminate between the control circuit terminal 87 and ground. If the test lamp illuminates, test the control circuit for a short to voltage.
  3. Verify that a test lamp illuminates between the B+ circuit terminal 85 and ground. If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.
  4. Verify that a test lamp illuminates between the B+ circuit terminal 30 and ground. If the test lamp does not illuminate, test the B+ circuit for an open/high resistance.
  5. Disconnect the harness connector at the appropriate headlamp.
  6. Test for less than 5 ohms between the headlamp ground circuit terminal 2 and ground If greater than the specified range, test the ground circuit for an open/high resistance.
  7. Connect the harness connector at the headlamp.
  8. Connect a 20 A fused jumper wire between the B+ circuit terminal 30 and the control circuit terminal 87. Verify the headlamp is activated. If the headlamp does not activate and the jumper wire fuse is good, test the control circuit for an open/high resistance. If the circuit tests normal, test or replace the headlamp. If the headlamp does not activate and the jumper wire fuse is open, test the control circuit for a short to ground. If the circuit tests normal, test or replace the headlamp.
  9. Connect a test lamp between the B+ circuit terminal 85 and the control circuit terminal 86.
  10. Command the Low Beams ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states. If the test lamp is always ON, test the control circuit for a short to ground. If the circuit tests normal, replace the BCM. If the test lamp is always OFF, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the BCM.
  11. If all circuits test normal, test or replace the LO beam relay.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Headlamp Ballast Replacement (Sedan)»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system) or «Headlamp Ballast Replacement (European)»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system__headlamp-ballast-replacement-european)
  2. «Headlamp Assembly or Headlamp Bulb and/or Cornering, Sidemarker, Park, Turn Signal Bulb Replacement (TT6)»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system) or «Headlamp Assembly or Headlamp Bulb and/or Cornering, Sidemarker, Park, Turn Signal Bulb Replacement (TT7)»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system) or «Headlamp Assembly or Headlamp Bulb and/or Cornering, Sidemarker, Park, Turn Signal Bulb Replacement (TT8)»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system__headlamp-assembly-or-headlamp-bulb-andor) or «Headlamp Assembly or Headlamp Bulb and/or Cornering, Sidemarker, Park, Turn Signal Bulb Replacement (Without TT6/TT7/TT8/T84/T85)»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system)
  3. «Underhood Electrical Center or Junction Block Replacement»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-repair-instructions)
  4. «Relay Replacement (Attached to Wire Harness)»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-repair-instructions) or «Relay Replacement (Within an Electrical Center)»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-repair-instructions)
  5. «Turn Signal Multifunction Switch Replacement»(/cadillac/cts/ii-2007-2014/remont/steering-column-switches/#steering-wheel-steering-column)
  6. «Control Module References»(/cadillac/cts/ii-2007-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM or IPC replacement, setup, and programming
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Left Front Strut Position Sensor 5 V ReferenceC0696 00C0615 08C0696 00
Right Front Strut Position Sensor 5 V ReferenceC0696 00C0620 08C0696 00
Left Rear Strut Position Sensor 5 V ReferenceC0696 00C0625 08C0696 00
Right Rear Strut Position Sensor 5 V ReferenceC0696 00C0630 08C0696 00
Left Front Strut Position Sensor SignalC0615 08C0615 08C0615 08, C0696 00C0615 55
Right Front Strut Position Sensor SignalC0620 08C0620 08C0620 08, C0696 00C0620 55
Left Rear Strut Position Sensor SignalC0625 08C0625 08C0625 08, C0696 00C0625 55
Right Rear Strut Position Sensor SignalC0630 08C0630 08C0630 08, C0696 00C0630 55
Headlamp Leveling Motor Control Circuit 1 - LeftB3435 02B3435 00B3435 00B3435 39, B3435 54
Headlamp Leveling Motor Control Circuit 2 - LeftB3435 02B3435 00B3435 00B3435 39, B3435 54
Headlamp Leveling Motor Control Circuit 3 - LeftB3435 02B3435 00B3435 00B3435 39, B3435 54
Headlamp Leveling Motor Control Circuit 4 - LeftB3435 02B3435 00B3435 00B3435 39, B3435 54
Headlamp Leveling Motor Control Circuit 1 - RightB3440 02B3440 00B3440 00B3440 39, B3440 54
Headlamp Leveling Motor Control Circuit 2 - RightB3440 02B3440 00B3440 00B3440 39, B3440 54
Headlamp Leveling Motor Control Circuit 3 - RightB3440 02B3440 00B3440 00B3440 39, B3440 54
Headlamp Leveling Motor Control Circuit 4 - RightB3440 02B3440 00B3440 00B3440 39, B3440 54
Left Front Strut Position Sensor Low ReferenceC0615 08
Right Front Strut Position Sensor Low ReferenceC0620 08
Left Rear Strut Position Sensor Low ReferenceC0625 08
Right Rear Strut Position Sensor Low ReferenceC0630 08

Each headlamp assembly contains a headlamp leveling motor that is controlled by the headlamp control module. The front and rear suspension position sensors provide the electronic suspension control (ESC) module with suspension position information. Each sensor receives a 5 V reference, signal, and low reference circuits from the ESC. The sensors are connected to the control arms of the front and rear suspension. As the vehicle travels, the suspension compresses and rebounds moving the suspension position sensor arms. This causes the signal output of the sensor to change. The ESC sends the suspension position sensor values to the headlamp control module via serial data. The headlamp control module compares the information from both suspension position sensors and adjusts the headlamp leveling as needed. The headlamp control module is wired to each headlamp leveling motor with 4 directional motor control circuits.

Schematic Reference

  1. «Headlights/Daytime Running Lights (DRL) Schematics»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system)
  2. «Electronic Suspension Control Schematics»(/cadillac/cts/ii-2007-2014/remont/electronic-suspension/#suspension-control-system-suspension-damping)

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

Ignition ON, with a scan tool, command the DHL Motor Control Up and Down while observing both headlamps. Both headlamps should operate to the Up and Down positions when commanded.

  1. Ignition OFF, disconnect the harness connector at the inoperative headlamp.
  2. Remove the AFS 15 A fuse.
  3. Ignition OFF, scan tool OFF, test for 10 ohms-25K ohms between each control circuit terminal listed below and ground. Headlamp leveling motor control terminal 1 Headlamp leveling motor control terminal 2 Headlamp leveling motor control terminal 3 Headlamp leveling motor control terminal 4 If greater than the specified range, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the headlamp control module. If less than the specified range, test the control circuit for a short to ground. If the circuit tests normal, replace the headlamp control module.
  4. Install the AFS 15 A fuse.
  5. Ignition ON, scan tool OFF, headlamps ON, verify that a test lamp does not illuminate between each control circuit terminal listed below and ground. Headlamp leveling motor control terminal 1 Headlamp leveling motor control terminal 2 Headlamp leveling motor control terminal 3 Headlamp leveling motor control terminal 4 If the test lamp illuminates, test the control circuit for a short to voltage. If the circuit tests normal, replace the headlamp control module.
  6. If all circuits test normal, replace the appropriate headlamp assembly.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Headlamp Assembly or Headlamp Bulb and/or Cornering, Sidemarker, Park, Turn Signal Bulb Replacement (TT6)»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system) or «Headlamp Assembly or Headlamp Bulb and/or Cornering, Sidemarker, Park, Turn Signal Bulb Replacement (TT7)»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system) or «Headlamp Assembly or Headlamp Bulb and/or Cornering, Sidemarker, Park, Turn Signal Bulb Replacement (TT8)»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system__headlamp-assembly-or-headlamp-bulb-andor) or «Headlamp Assembly or Headlamp Bulb and/or Cornering, Sidemarker, Park, Turn Signal Bulb Replacement (Without TT6/TT7/TT8/T84/T85)»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system)
  2. «Control Module References»(/cadillac/cts/ii-2007-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for headlamp control module replacement, setup, and programming
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Headlamp Leveling Sensor 5 Volt Reference - FrontB3410 02B3410 02B3410 01
Headlamp Leveling Sensor 5 Volt Reference - RearB3420 02B3420 02B3420 01
Headlamp Leveling Sensor Signal - FrontB3410 03B3410 03B3410 07
Headlamp Leveling Sensor Signal - RearB3420 03B3420 03B3420 07
Headlamp Leveling Motor Control Circuit 1 - LeftB3435 02B3435 00B3435 00B3435 39, B3435 54
Headlamp Leveling Motor Control Circuit 2 - LeftB3435 02B3435 00B3435 00B3435 39, B3435 54
Headlamp Leveling Motor Control Circuit 3 - LeftB3435 02B3435 00B3435 00B3435 39, B3435 54
Headlamp Leveling Motor Control Circuit 4 - LeftB3435 02B3435 00B3435 00B3435 39, B3435 54
Headlamp Leveling Motor Control Circuit 1 - RightB3440 02B3440 00B3440 00B3440 39, B3440 54
Headlamp Leveling Motor Control Circuit 2 - RightB3440 02B3440 00B3440 00B3440 39, B3440 54
Headlamp Leveling Motor Control Circuit 3 - RightB3440 02B3440 00B3440 00B3440 39, B3440 54
Headlamp Leveling Motor Control Circuit 4 - RightB3440 02B3440 00B3440 00B3440 39, B3440 54
Headlamp Leveling Sensor Low Reference - Front11
Headlamp Leveling Sensor Low Reference - Rear11
1. Headlamp Leveling Malfunction

Each headlamp assembly contains a headlamp leveling motor that is controlled by the headlamp control module. The front and rear suspension position sensors provide the headlamp control module with suspension position information. Each sensor receives a 5-volt reference, signal, and low reference circuits from the headlamp control module. The sensors are connected to the control arms of the front and rear suspension. As the vehicle travels, the suspension compresses and rebounds moving the suspension position sensor arms. This causes the signal output of the sensor to change. The headlamp control module compares the information from both suspension position sensors and adjusts the headlamp leveling as needed. The headlamp control module is wired to each headlamp leveling motor with 4 directional motor control circuits.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition ON, with a scan tool, command the DHL Motor Control Up and Down while observing both headlamps. Both headlamps should operate to the Up and Down positions when commanded. If the headlamps do not operate to the Up and Down positions when commanded, refer to Headlamp Leveling Actuator Malfunction in «Circuit/System Testing»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system) .
  2. Observe the scan tool Front Leveling Position Sensor voltage parameter. The parameter should be between 0.5 and 4.9 volts. If the parameter is not within the specified range, refer to Headlamp Leveling Sensor Malfunction in «Circuit/System Testing»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system) .
  3. Observe the scan tool Rear Leveling Position Sensor voltage parameter. The parameter should be between 0.5 and 4.9 volts. If the parameter is not within the specified range, refer to Headlamp Leveling Sensor Malfunction in «Circuit/System Testing»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system) .

Headlamp Leveling Actuator Malfunction

  1. Ignition OFF, disconnect the harness connector at the inoperative headlamp.
  2. Remove the AFS 15A fuse.
  3. Ignition OFF, scan tool OFF, test for 10 ohms -25K ohms between each control circuit terminal listed below and ground. Headlamp leveling motor control terminal 1 Headlamp leveling motor control terminal 2 Headlamp leveling motor control terminal 3 Headlamp leveling motor control terminal 4 If greater than the specified range, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the headlamp control module. If less than the specified range, test the control circuit for a short to ground. If the circuit tests normal, replace the headlamp control module.
  4. Install the AFS 15A fuse.
  5. Ignition ON, scan tool OFF, headlamps ON, verify that a test lamp does not illuminate between each control circuit terminal listed below and ground. Headlamp leveling motor control terminal 1 Headlamp leveling motor control terminal 2 Headlamp leveling motor control terminal 3 Headlamp leveling motor control terminal 4 If the test lamp illuminates, test the control circuit for a short to voltage. If the circuit tests normal, replace the headlamp control module.
  6. If all circuits test normal, replace the appropriate headlamp assembly.

Headlamp Leveling Sensor Malfunction

  1. Ignition OFF, disconnect the harness connector at the appropriate headlamp leveling sensor.
  2. Ignition OFF, test for less than 10 ohms between the low reference circuit terminal C and ground. If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the headlamp control module.
  3. Ignition ON, test for 4.8-5.2 volts between the 5-volt reference circuit terminal A and ground. If less than the specified range, test the 5-volt reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the headlamp control module. If greater than the specified range, test the 5-volt reference circuit for a short to voltage. If the circuit tests normal, replace the headlamp control module.
  4. Verify the scan tool Leveling Position Sensor parameter is less than 0.5-volts. If greater than the specified range, test the signal circuit terminal B for a short to voltage. If the circuit tests normal, replace the headlamp control module.
  5. Install a 3A fused jumper wire between the signal circuit terminal B and the 5-volt reference circuit terminal A. Verify the scan tool Leveling Position Sensor parameter is greater than 4.8-volts. If less than the specified range, test the signal circuit for short to ground or an open/high resistance. If the circuit tests normal, replace the headlamp control module.
  6. If all circuits test normal, test or replace the appropriate headlamp leveling sensor.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Headlamp Assembly or Headlamp Bulb and/or Cornering, Sidemarker, Park, Turn Signal Bulb Replacement (TT6)»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system) or «Headlamp Assembly or Headlamp Bulb and/or Cornering, Sidemarker, Park, Turn Signal Bulb Replacement (TT7)»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system) or «Headlamp Assembly or Headlamp Bulb and/or Cornering, Sidemarker, Park, Turn Signal Bulb Replacement (TT8)»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system__headlamp-assembly-or-headlamp-bulb-andor) or «Headlamp Assembly or Headlamp Bulb and/or Cornering, Sidemarker, Park, Turn Signal Bulb Replacement (Without TT6/TT7/TT8/T84/T85)»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system)
  2. «Headlamp Leveling Front Suspension Height Sensor Replacement»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system)
  3. «Headlamp Leveling Rear Suspension Height Sensor Replacement»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system)
  4. «Control Module References»(/cadillac/cts/ii-2007-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for headlamp control module replacement, setup, and programming
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Accent Lamp Signal - Driver Door Module111
Accent Lamp Signal - Passenger Door Module111
Accent Lamp ControlB261A 0211
Accent Lamp Driver Door Ground1
Accent Lamp Driver Door Handle Ground1
Accent Lamp Passenger Door Ground1
Accent Lamp Passenger Door Handle Ground1
Accent Lamp Left I/P Ground1
Accent Lamp Lower Left I/P Ground1
Accent Lamp Left Rear Door Ground1
Accent Lamp Left Rear Door Handle Ground1
Accent Lamp Driver Seat Ground1
Accent Lamp Overhead Console Ground1
Accent Lamp Right I/P Ground1
Accent Lamp Lower Right I/P Ground1
Accent Lamp Right Rear Door Ground1
Accent Lamp Right Rear Door Handle Ground1
Accent Lamp Passenger Seat Ground1
1. Interior Accent Lighting Malfunction

The instrument panel (I/P) dimmer switch is used to increase and decrease the brightness of the interior backlighting components. The I/P dimmer switch provides a voltage signal that will increase as the brightness of the light are increased and decrease as the brightness of the lights are decreased. The body control module (BCM) provides a low reference signal and a B+ voltage reference to the I/P dimmer switch. When the I/P dimmer switch is placed in the desired position, the dimmed voltage setting is applied from the I/P dimmer switch through the I/P dimmer switch signal circuit to the BCM. The BCM interprets the signal and applies the dimmed voltage to the individual accent lamps via the accent lamps control circuit. The BCM also sends a serial data message to the driver and front passenger door control modules requesting the accent lamps on both doors be dimmed to the requested level. The driver and front passenger door modules respond by applying the appropriate voltage for the requested dim level to the accent lights.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition ON, observe the scan tool Dimming Control Signal parameter while operating the dimmer switch from high to low. The reading should change from a high percent to a low percent as the switch is activated. If the reading does not change, refer to «Interior Backlighting Malfunction»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system) .
  2. Ignition ON, park lamps ON, observe the accent lamps located on the driver and front passenger doors. All door accent lamps should be illuminated. If the driver or front passenger door accent lamps are not illuminated, refer to Accent Lamps Malfunction - Front Doors in «Circuit/System Testing»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system) .

Accent Lamps Malfunction

  1. Ignition OFF, disconnect the harness connector at the inoperative accent lamp.
  2. Ignition OFF, test for less than 5.0 ohms between the ground circuit terminal and ground. If greater than the specified range, test the ground circuit for an open/high resistance.
  3. Ignition OFF, park lamps OFF, verify that a test lamp does not illuminate between the control circuit terminal and ground. If the test lamp illuminates, test the control circuit for a short to voltage. If the circuit tests normal, replace the BCM.
  4. Ignition ON, park lamps ON, verify that a test lamp illuminates between the control circuit terminal and ground. If the test lamp does not illuminate, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM.
  5. If all circuits test normal, replace the inoperative accent lamp.

Accent Lamps Malfunction - Front Doors

  1. Ignition OFF, disconnect the harness connector at the inoperative door accent lamp.
  2. Ignition OFF, verify that a test lamp illuminates between B+ and the ground circuit terminal A. If the test lamp does not illuminate, test the ground circuit for an open/high resistance.
  3. Ignition OFF, park lamps OFF, verify that a test lamp does not illuminate between the control circuit terminal B and ground. If the test lamp illuminates, test the control circuit for a short to voltage. If the circuit tests normal, replace the appropriate door control module.
  4. Ignition ON, park lamps ON, verify that a test lamp illuminates between the control circuit terminal and ground. If the test lamp does not illuminate, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the appropriate door control module.
  5. If all circuits test normal, replace the inoperative accent lamp.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Luminescent Lamp Replacement - Driver or Passenger Seat»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system)
  2. «Door Lamp Replacement»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system)
  3. «Instrument Panel Flood Lamp Replacement - Left Side»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system)
  4. «Instrument Panel Flood Lamp Replacement - Right Side»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system)
  5. «Control Module References»(/cadillac/cts/ii-2007-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM, DDM, or PDM replacement, setup, and programming
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Body Control Module (BCM) 1 Fuse B+B1395 03B1395 03
Body Control Module (BCM) 2 Fuse B+33
Body Control Module (BCM) 7 Fuse B+B2652 00B2652 00
I/P Dimming Voltage ReferenceB1395 0311
I/P Dimmer Switch SignalB1395 0311
I/P Lamps Dimmer Switch SignalB2652 0022
Indicator Dimming ControlB2625 0033
LED Backlight Dimming ControlB2610 0033
Memory Switch Backlight Control444
Memory Switch Backlight Low Reference4
I/P Dimmer Switch Ground1
1. Dimmer Switch Malfunction 2. Interior Backlighting Malfunction - Incandescent 3. Interior Backlighting Malfunction - LED 4. Memory Switch Indicator Malfunction

The instrument panel (I/P) lamp dimmer switch is used to increase and decrease the brightness of the interior backlighting components. The I/P dimmer switch provides a voltage signal that will increase as the brightness of the lights are increased and decrease as the brightness of the lights are decreased. The body control module (BCM) provides a low reference signal and a B+ voltage reference to the I/P dimmer switch. When the I/P dimmer switch is placed in the desired position, the dimmed voltage setting is applied from the I/P dimmer switch through the I/P dimmer switch signal circuit to the BCM. The BCM interprets the signal and applies the dimmed voltage to the I/P lamps supply voltage circuit and the interior backlighting components dim to the requested level. The BCM also sends a serial data message to the driver and front passenger door modules indicating the dimmed level. The door modules respond by supplying there respective switch backlighting with the appropriate voltage for the desired dimmed setting.

Schematic Reference

  1. «Interior Lights Dimming Schematics»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system)
  2. «Driver Seat Schematics»(/cadillac/cts/ii-2007-2014/remont/seats/#power-seat-system)

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition ON, observe the scan tool Dimming Control Signal parameter while operating the dimmer switch from high to low. The reading should change from a high percent to a low percent as the switch is activated. If the reading does not change, refer to I/P Dimmer Switch Malfunction in «Circuit/System Testing»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system) .
  2. With a scan tool, perform the Integrated Sw. Backlighting Test for the driver door switch. The driver door switch backlighting should illuminate from high to low. If the driver door switch backlighting does not operate as described, replace the driver door module (DDM).
  3. With a scan tool, perform the Integrated Sw. Backlighting Test for the passenger door switch. The passenger door switch backlighting should illuminate from high to low. If the passenger door switch backlighting does not operate as described, replace the driver door module (PDM).
  4. With a scan tool, perform the Non-Integrated Backlighting Test for the driver door switch. The memory switch backlighting should turn ON and OFF. If the memory switch backlighting does not operate as described, refer to Memory Switch Indicator Malfunction in «Circuit/System Testing»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system) .

I/P Dimmer Switch Malfunction

  1. Ignition OFF, disconnect the harness connector at the I/P Dimmer switch.
  2. Ignition OFF, verify that a test lamp illuminates between B+ and the ground circuit terminal 10. If the test lamp does not illuminate, test the ground circuit for an open/high resistance.
  3. Ignition ON, verify the scan tool Dimming Control Signal parameter is less than 0.1 volts. If greater than the specified range, test the signal circuit terminal 9 for a short to voltage. If the circuit tests normal, replace the BCM.
  4. Ignition ON, test for B+ between the voltage reference circuit terminal 5 and ground. If less than the specified range, test the B+ reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM.
  5. Install a 3A fused jumper wire between the signal circuit terminal 9 and the B+ reference circuit terminal 5. Verify the scan tool Dimming Control Signal parameter is greater than 2.5 volts. If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM.
  6. If all circuits test normal, test or replace the I/P dimmer switch.

Interior Backlighting Malfunction - Incandescent

  1. Ignition OFF, disconnect the harness connector at the component with the inoperative incandescent backlighting.
  2. Ignition OFF, test for less than 5 ohms between the ground circuit and ground. If greater than the specified value, test the ground circuit for an open/high resistance.
  3. Connect a test lamp between the control circuit and ground.
  4. Command the Incandescent Dimming Control ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states. If the test lamp is always OFF, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM. If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the BCM.
  5. If all circuits test normal, test or replace the component with the inoperative incandescent backlighting.

Interior Backlighting Malfunction - LED

  1. Ignition OFF, disconnect the X3 harness connector at the BCM.
  2. Ignition ON, verify that a test lamp illuminates between the BCM 2 fuse B+ circuit terminal 2 and ground. If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.
  3. Ignition OFF, reconnect the X3 harness connector at the BCM.
  4. Disconnect the harness connector at the component with the inoperative LED backlighting.
  5. Ignition OFF, scan tool OFF, interior lamps OFF, doors CLOSED, test for less than 5 ohms between the ground circuit and ground. If greater than the specified value, test the ground circuit for an open/high resistance.
  6. Connect a test lamp between the control circuit and ground.
  7. Command the LED Dimming Control ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states. If the test lamp is always OFF, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM. If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the BCM.
  8. If all circuits test normal, test or replace the component with the inoperative LED backlighting.

Memory Switch Indicator Malfunction

  1. Ignition OFF, disconnect the X4 harness connector at the driver door module.
  2. Connect a test lamp between the control circuit terminal 13 and the low reference circuit terminal 4 at the drive door module terminal pins.
  3. Command the Non-Integrated Backlighting Test ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states. If the test lamp does not turn ON and OFF when commanded, replace the driver door module.
  4. If all circuits test normal, replace the memory switch.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Rear Side Door Window Switch Replacement»(/cadillac/cts/ii-2007-2014/remont/heated-glassdefoggers/#fixed-and-moveable-windows-system)
  2. «Driver Information Display Switch Replacement»(/cadillac/cts/ii-2007-2014/remont/gauges-instrument-panels/#instrument-panel-system-displays-gauges)
  3. «Instrument Panel Lamp Dimmer Switch Replacement»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system)
  4. «Steering Wheel Control Switch Assembly Replacement»(/cadillac/cts/ii-2007-2014/remont/memory-modules/#secondary-and-configurable-customer-control-system)
  5. «Door Lock and Side Window Switch Replacement - Driver Side»(/cadillac/cts/ii-2007-2014/remont/door-locks-anti-theft-systems/#door-lock-system-door-handles)
  6. «Door Lock and Side Window Switch Replacement - Passenger Side»(/cadillac/cts/ii-2007-2014/remont/door-locks-anti-theft-systems/#door-lock-system-door-handles)
  7. «Driver Seat Adjuster Memory Switch Replacement»(/cadillac/cts/ii-2007-2014/remont/seats/#power-seat-system)
  8. «Control Module References»(/cadillac/cts/ii-2007-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM, DDM, or PDM replacement, setup, and programming
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Park Lamp Switch ON Signal222
LT/POS/LP Relay Control11B2585 00
License Lamp Control111
Park Lamp Control111
License Lamp Ground1
Park Lamps - LF Ground1
Park Lamps - RF Ground1
Tail/Stop and Turn Signal Lamps - LR Ground1
Tail/Stop and Turn Signal Lamps - RR Ground1
Turn Signal/Multifunction Switch Ground2
1. Park, License, and/or Tail Lamps Malfunction 2. Park Lamp Switch Malfunction

Battery positive voltage is applied at all times to both the coil and switch sides of the LT/POS/LP relay located in the rear fuse block. The turn signal/multifunction switch is suppled with ground at G200 at all times. When the headlamp switch is placed in either the HEAD or PARK position, ground is applied to the park lamp signal circuit to the body control module (BCM). The BCM responds by applying ground to the park lamp relay control circuit. This energizes the park lamp relay coil causing the relay switch contacts to close allowing battery voltage to flow through the LT/POS/LP and RT/POS/LP fuses to all of the park, tail, license, and marker lamps.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

Ignition ON, observe the scan tool Park Lamp Switch parameter while cycling the park lamp switch ON and OFF. The parameter should change between Active and Inactive.

  1. If the parameter does not change between the commanded states, refer to Park Lamp Switch Malfunction in «Circuit/System Testing»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system) .
  2. If the parameter changes between the commanded states, refer to Park, License, and/or Tail Lamps Malfunction in «Circuit/System Testing»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system) .

Park Lamp Switch Malfunction

  1. Ignition OFF, disconnect the X1 harness connector at the turn signal/multifunction switch.
  2. Ignition OFF, verify that a test lamp illuminates between B+ and the ground circuit terminal 9. If the test lamp does not illuminate, test the ground circuit for an open/high resistance.
  3. Ignition ON, verify the scan tool Park Lamp Switch parameter is Inactive. If not the specified value, test the signal circuit terminal 6 for a short to ground. If the circuit tests normal, replace the BCM.
  4. Install a 3A fused jumper wire between the signal circuit terminal 6 and ground. Verify the scan tool Park Lamp Switch parameter is Active. If not the specified value, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the BCM.
  5. If all circuits test normal, test or replace the turn signal/multifunction switch.

Park, License, and/or Tail Lamps Malfunction

  1. Ignition OFF, remove the fuse of the inoperative park/marker lamps and inspect. If the fuse is OPEN, test the control circuit of the blown fuse for a short to ground.
  2. Install the fuse.
  3. Ignition OFF, disconnect the LT/POS/LP relay.
  4. Ignition ON, verify that a test lamp does not illuminate between the control circuit terminal 87 and ground. If the test lamp illuminates, test the control circuit for a short to voltage.
  5. Verify that a test lamp illuminates between the B+ circuit terminal 30 and ground. If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance. If the circuit tests normal and the B+ circuit fuse is open, test the control circuit terminal 87 for a short to ground. If the circuit tests normal, test or replace the park lamp relay.
  6. Verify that a test lamp illuminates between the B+ circuit terminal 85 and ground. If the test lamp does not illuminate, test the B+ circuit for an open/high resistance.
  7. Disconnect the harness connector at the inoperative park/license/marker lamp.
  8. Ignition OFF, exterior lamps OFF, test for less than 5 ohms between the ground circuit and ground. If greater than the specified range, test the ground circuit for an open/high resistance.
  9. Connect the harness connector at the inoperative park/license/marker lamp.
  10. Connect a 20A fused jumper wire between the B+ circuit terminal 30 and the control circuit terminal 87. Verify the park/marker lamps illuminate. If the park/marker lamps do not illuminate, test the control circuit for an open/high resistance. If the circuit tests normal, replace the inoperative park/license/marker lamp.
  11. Connect a test lamp between the B+ circuit terminal 85 and the control circuit terminal 86.
  12. Command the Park Lamps ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states. If the test lamp is always ON, test the control circuit for a short to ground. If the circuit tests normal, replace the BCM. If the test lamp is always OFF, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the BCM.
  13. If all circuits test normal, test or replace the park lamp relay.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Rear License Plate Lamp Replacement (Sedan, V-Series)»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system) or «Rear License Plate Lamp Replacement (Wagon)»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system)
  2. «Tail Lamp Replacement (Sedan, V-Series)»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system) or «Tail Lamp Replacement (Wagon)»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system)
  3. «Parking and Turn Signal Lamp Bulb Replacement»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system)
  4. «Relay Replacement (Attached to Wire Harness)»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-repair-instructions) or «Relay Replacement (Within an Electrical Center)»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-repair-instructions)
  5. «Turn Signal Multifunction Switch Replacement»(/cadillac/cts/ii-2007-2014/remont/steering-column-switches/#steering-wheel-steering-column)
  6. «Control Module References»(/cadillac/cts/ii-2007-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM replacement, setup, and programming
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Park Lamp Switch ON Signal222
LT/POS/LP Relay Control11B2590 00
RT/POS/LP Relay Control11B2595 00
Park Lamp Relay Control111
License Lamp Control111
Park Lamp Control111
License Lamp Ground1
Park Lamp Relay Ground1
Park Lamps - LF Ground1
Park Lamps - RF Ground1
Tail/Stop and Turn Signal Lamps - LR Ground1
Tail/Stop and Turn Signal Lamps - RR Ground1
Turn Signal/Multifunction Switch Ground2
1. Park, License, and/or Tail Lamps Malfunction 2. Park Lamp Switch Malfunction

Battery positive voltage is applied at all times to both the coil and switch sides of the LT/POS/LP and RT/POS/LP relays located in the rear fuse block. The turn signal/multifunction switch is suppled with ground at G200 at all times. When the headlamp switch is placed in either the HEAD or PARK position, ground is applied to the park lamp signal circuit to the body control module (BCM). The BCM responds by applying ground to the left and right park lamp relay control circuits. This energizes the left and right park lamp relay coils causing the relay switch contacts to close allowing battery voltage to flow through the LT/POS/LP and RT/POS/LP fuses to all of the park, tail, license, and marker lamps.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition ON, observe the scan tool Park Lamp Switch parameter while cycling the park lamp switch between the ON and OFF positions. The parameter should change between Active and Inactive. If the parameter does not change between the commanded states, refer to Park Lamp Switch Malfunction in «Circuit/System Testing»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system) .
  2. Ignition ON, park lamps ON, observe all park/license/marker lamps and license lamps. All park/license/marker lamps should be illuminated. If all park lamps are inoperative, refer to Park, Marker, and/or Tail Lamps Malfunction in «Circuit/System Testing»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system) . If only the license lamps are inoperative, refer to License Lamps Malfunction in «Circuit/System Testing»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system) .

Park Lamp Switch Malfunction

  1. Ignition OFF, disconnect the X1 harness connector at the turn signal/multifunction switch.
  2. Ignition OFF, verify that a test lamp illuminates between B+ and the ground circuit terminal 9. If the test lamp does not illuminate, test the ground circuit for an open/high resistance.
  3. Ignition ON, verify the scan tool Park Lamp Switch parameter is Inactive. If not the specified value, test the signal circuit terminal 6 for a short to ground. If the circuit tests normal, replace the BCM.
  4. Install a 3A fused jumper wire between the signal circuit terminal 6 and ground. Verify the scan tool Park Lamp Switch parameter is Active. If not the specified value, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the BCM.
  5. If all circuits test normal, test or replace the turn signal/multifunction switch.

Park, Marker, and/or Tail Lamps Malfunction

  1. Ignition OFF, remove the fuse of the inoperative park/marker lamps and inspect. If the fuse is OPEN, test the B+ circuit of the blown fuse for a short to ground.
  2. Install the fuse.
  3. Ignition OFF, disconnect the appropriate position lamp relay.
  4. Ignition ON, verify that a test lamp does not illuminate between the control circuit terminal 87 and ground. If the test lamp illuminates, test the control circuit for a short to voltage.
  5. Verify that a test lamp illuminates between the B+ circuit terminal 30 and ground. If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance. If the circuit tests normal and the B+ circuit fuse is open, test the control circuit terminal 87 for a short to ground. If the circuit tests normal, test or replace the appropriate position lamp relay.
  6. Verify that a test lamp illuminates between the B+ circuit terminal 85 and ground. If the test lamp does not illuminate, test the B+ circuit for an open/high resistance.
  7. Disconnect the harness connector at the inoperative park/marker lamp.
  8. Ignition OFF, exterior lamps OFF, test for less than 5 ohms between the ground circuit and ground. If greater than the specified range, test the ground circuit for an open/high resistance.
  9. Connect the harness connector at the inoperative park/marker lamp.
  10. Connect a 10A fused jumper wire between the B+ circuit terminal 30 and the control circuit terminal 87. Verify the appropriate park/marker lamps illuminate. If the park/marker lamps do not illuminate, test the control circuit for an open/high resistance. If the circuit tests normal, replace the inoperative park/marker lamp.
  11. Connect a test lamp between the B+ circuit terminal 85 and the control circuit terminal 86.
  12. Command the Park Lamps ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states. If the test lamp is always ON, test the control circuit for a short to ground. If the circuit tests normal, replace the BCM. If the test lamp is always OFF, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the BCM.
  13. If all circuits test normal, test or replace the appropriate position lamp relay.

License Lamps Malfunction

  1. Ignition OFF, disconnect the park lamp relay.
  2. Ignition OFF, exterior lamps OFF, test for less than 5 ohms between the ground circuit terminal A1 and ground If greater than the specified range, test the ground circuit for an open/high resistance.
  3. Ignition ON, verify that a test lamp does not illuminate between the control circuit terminal A2 and ground. If the test lamp illuminates, test the control circuit for a short to voltage.
  4. Ignition ON, park lamps ON, verify that a test lamp illuminates between the B+ circuit terminal C1 and ground. If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance. If the circuit tests normal and the B+ circuit fuse is open, test the control circuit terminal A2 for a short to ground. If the circuit tests normal, test or replace the park lamp relay.
  5. Verify that a test lamp illuminates between the B+ circuit terminal C2 and ground. If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.
  6. Disconnect the harness connector at the inoperative license lamp.
  7. Ignition OFF, exterior lamps OFF, test for less than 5 ohms between the ground circuit terminal 2 and ground. If greater than the specified range, test the ground circuit for an open/high resistance.
  8. Connect the harness connector at the inoperative license lamp.
  9. Connect a 10A fused jumper wire between the B+ circuit terminal C1 and the control circuit terminal A2.
  10. Ignition ON, park lamps ON, verify the license lamps illuminate. If the license lamps do not illuminate, test the control circuit for an open/high resistance. If the circuit tests normal, replace the inoperative license lamp.
  11. If all circuits test normal, test or replace the park lamp relay.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Rear License Plate Lamp Replacement (Sedan, V-Series)»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system) or «Rear License Plate Lamp Replacement (Wagon)»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system)
  2. «Tail Lamp Replacement (Sedan, V-Series)»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system) or «Tail Lamp Replacement (Wagon)»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system)
  3. «Parking and Turn Signal Lamp Bulb Replacement»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system)
  4. «Relay Replacement (Attached to Wire Harness)»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-repair-instructions) or «Relay Replacement (Within an Electrical Center)»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-repair-instructions)
  5. «Turn Signal Multifunction Switch Replacement»(/cadillac/cts/ii-2007-2014/remont/steering-column-switches/#steering-wheel-steering-column)
  6. «Control Module References»(/cadillac/cts/ii-2007-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM replacement, setup, and programming
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Body Control Module (BCM) 5 Fuse B+1, 21, 2
Body Control Module (BCM) 6 Fuse B+1, 21, 2
Brake Position Sensor 5-Volt ReferenceC0277 06, C0890 03C0277 061, 2
Stop Lamp Relay Switch B+ - European22
Brake Applied SignalC0297 00 and P0571 0044
Brake Position Sensor SignalC0277 06C0277 06C0277 07C0277 09
Center High Mounted Stop Lamp (CHMSL) ControlB3884 002, 32, 3
Stop Lamp Relay Control - EuropeanB3445 002, 32, 3
Left Rear Stop/Turn Lamp Control1, 21, 21, 2
Right Rear Stop/Turn Lamp Control1, 21, 21, 2
Brake Position Sensor Low ReferenceC0277 071, 2
Center High Mounted Stop Lamp (CHMSL) Ground33
Left Rear Stop/Turn Lamp Ground1, 21, 2
Right Rear Stop/Turn Lamp Ground1, 21, 2
Stop Lamp Relay Ground - European22
1. Stop Lamps Malfunction - North America 2. Stop Lamps Malfunction - European 3. Center High Mounted Stop Lamp (CHMSL) Malfunction 4. Cruise Control Malfunction

The brake pedal position sensor is used to sense the action of the driver application of the brake pedal. The brake pedal position sensor provides an analog voltage signal that will increase as the brake pedal is applied. The body control module (BCM) provides a low reference signal and a 5-volt reference voltage to the brake pedal position sensor. When the variable signal reaches a voltage threshold indicating the brakes have been applied, the BCM will apply battery voltage to the right and left stop lamp control circuits, transmission control module (TCM), engine control module (ECM), and center high mounted stop lamp (CHMSL) control circuit.

The brake pedal position sensor is used to sense the action of the driver application of the brake pedal. The brake pedal position sensor provides an analog voltage signal that will increase as the brake pedal is applied. The body control module (BCM) provides a low reference signal and a 5-volt reference voltage to the brake pedal position sensor. When the variable signal reaches a voltage threshold indicating the brakes have been applied, the BCM will apply battery voltage to stop lamp relay coil side control circuit, transmission control module (TCM), engine control module (ECM), and center high mounted stop lamp (CHMSL). When the stop lamp relay receives battery voltage from the BCM, the relay coil is energized and the stop lamp relay switch contacts close applying battery voltage from the STOP LAMPS fuse to illuminate the rear stop lamps and trailer stop lamps.

The stop lamps will not illuminate unless the ignition is in the ON position. For more detailed information concerning stop lamp operation, refer to Exterior Lighting Systems Description and Operation .

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition ON, observe the scan tool Brake Applied Output Signal parameter as you apply and unapply the brake pedal. The reading should cycle between OFF and ON as the brake pedal is applied and released. If the reading does not change as the brake pedal is applied and released, refer to Brake Pedal Position Sensor (BPPS) Malfunction in «Circuit/System Testing»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system) .
  2. With a scan tool, command the LR Turn Signal ON and OFF. The LR turn signal should turn ON and OFF when changing between the commanded states. If the LR turn signal does not illuminate when commanded, refer to Stop Lamps Malfunction in «Circuit/System Testing»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system) .
  3. With a scan tool, command the RR Turn Signal ON and OFF. The RR turn signal should turn ON and OFF when changing between the commanded states. If the RR turn signal does not illuminate when commanded, refer to Stop Lamps Malfunction in «Circuit/System Testing»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system) .

Stop Lamps Malfunction - North America

  1. Ignition OFF, disconnect the X4 harness connector at the BCM.
  2. Verify that a test lamp illuminates between the BCM 5 fuse B+ circuit terminal 1 and ground. If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.
  3. Verify that a test lamp illuminates between the BCM 6 fuse B+ circuit terminal 3 and ground. If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.
  4. Ignition OFF, reconnect the X4 harness connector at the BCM.
  5. Disconnect the harness connector at the inoperative stop lamp.
  6. Ignition OFF, exterior lamps OFF, test for less than 5.0 ohms between the ground circuit terminal C and ground. If greater than the specified range, test the ground circuit for an open/high resistance.
  7. Connect a test lamp between the control circuit terminal B and ground.
  8. Ignition ON, command the appropriate stop lamp ON and OFF by commanding the appropriate Rear Turn Signal parameter ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states. If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the BCM. If the test lamp is always OFF, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM.
  9. If all circuits test normal, replace the inoperative tail lamp assembly.

Stop Lamps Malfunction - European

  1. Ignition OFF, disconnect the X4 harness connector at the BCM.
  2. Ignition ON, verify that a test lamp illuminates between the BCM 5 fuse B+ circuit terminal 1 and ground. If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.
  3. Ignition ON, verify that a test lamp illuminates between the BCM 6 fuse B+ circuit terminal 3 and ground. If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.
  4. Ignition OFF, reconnect the X4 harness connector at the BCM.
  5. Disconnect the stop lamp relay.
  6. Ignition OFF, exterior lamps OFF, test for less than 5.0 ohms between the ground circuit terminal 85 and ground. If greater than the specified range, test the ground circuit for an open/high resistance.
  7. Ignition ON, verify that a test lamp does not illuminate between the control circuit terminal 87 and ground. If the test lamp illuminates, test the control circuit for a short to voltage.
  8. Verify that a test lamp illuminates between the B+ circuit terminal 30 and ground. If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance. If the circuit tests normal and the B+ circuit fuse is open, test the relay control circuit terminal 87 for a short to ground. If the circuit tests normal, test or replace the stop lamp relay.
  9. Connect a test lamp between the control circuit terminal 86 and the ground circuit terminal 85.
  10. Ignition ON, command the stop lamps ON and OFF by applying and releasing the brake pedal. The test lamp should turn ON and OFF when changing between the commanded states. If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the BCM. If the test lamp is always OFF, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM.
  11. Disconnect the harness connector at the inoperative stop lamp.
  12. Ignition OFF, exterior lamps OFF, test for less than 5.0 ohms between the ground circuit terminal H and ground. If greater than the specified range, test the ground circuit for an open/high resistance.
  13. Connect a test lamp between the control circuit terminal B and the ground circuit terminal H.
  14. Ignition ON, command the stop lamps ON and OFF by commanding the appropriate rear turn signal parameter ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states. If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the BCM. If the test lamp is always OFF, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM.
  15. If all circuits test normal, replace the inoperative tail lamp assembly.

Center High Mounted Stop Lamp (CHMSL) Malfunction

  1. Ignition OFF, disconnect the harness connector at the CHMSL.
  2. Ignition OFF, exterior lamps OFF, test for less than 5.0 ohms between the ground circuit terminal B and ground. If greater than the specified range, test the ground circuit for an open/high resistance.
  3. Connect a test lamp between the control circuit terminal A and the ground circuit terminal B.
  4. Ignition ON, command the stop lamps ON and OFF by applying and releasing the brake pedal. The test lamp should turn ON and OFF when changing between the commanded states. If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the BCM. If the test lamp is always OFF, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM.
  5. If all circuits test normal, test or replace the CHMSL.

Brake Pedal Position Sensor (BPPS) Malfunction

  1. Ignition OFF, disconnect the harness connector at the BPPS.
  2. Ignition ON, verify that a test lamp does not illuminate between the low reference circuit terminal A and ground. If the test lamp illuminates, test the low reference circuit for a short to voltage. If the circuit tests normal, replace the BCM.
  3. Ignition ON, test for 4.8 volts and 5.2 volts between the 5-volt reference circuit terminal C and ground. If less than the specified range, test the 5-volt reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM. If greater than the specified range, test the 5-volt reference circuit for a short to voltage. If the circuit tests normal, replace the BCM.
  4. If all circuits test normal, replace the BPPS.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «High Mount Stop Lamp Replacement (Sedan, V-Series)»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system) or «High Mount Stop Lamp Replacement (Wagon)»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system)
  2. «Tail Lamp Replacement (Sedan, V-Series)»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system) or «Tail Lamp Replacement (Wagon)»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system)
  3. «Relay Replacement (Attached to Wire Harness)»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-repair-instructions) or «Relay Replacement (Within an Electrical Center)»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-repair-instructions)
  4. «Brake Pedal Position Sensor Replacement»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system__brake-pedal-position-sensor-replacement)
  5. «Control Module References»(/cadillac/cts/ii-2007-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM replacement, setup, and programming
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Auxiliary Body Control Module B+B3891 02B3891 05B3891 05
Trailer Left Turn Relay B+33
Trailer Right Turn Relay B+33
Trailer Left Turn Relay Signal333
Trailer Right Turn Relay Signal333
Trailer Backup Lamp Relay Control222
Trailer Left Turn Relay Control333
Trailer Right Turn Relay Control333
Trailer Parking Lamps Control444
Trailer Stop Lamp Control111
Trailer Backup Lamp Relay Low Reference2
Trailer Left Turn Relay Ground3
Trailer Right Turn Relay Ground3
1. Trailer Stop Lamps Malfunction 2. Trailer Backup Lamps Malfunction 3. Trailer Turn Signal Lamps Malfunction 4. Trailer Parking Lamps Malfunction

The vehicle's trailer lighting control system contains an auxiliary body control module (BCM) to send lighting commands to the trailer lighting system. The vehicle's trailer wiring harness and auxiliary BCM is integrated into the vehicle wiring harness and controls the signals to the trailer connector. Battery voltage is supplied to the auxiliary BCM from the REAR/FOG/XBCM fuse located in the rear fuse block.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

Trailer Brake Lamp Circuit Malfunction

  1. Ignition OFF, test for less than 1 ohms between the appropriate trailer connector ground circuit terminal and ground. If greater than the specified range, test the ground circuit for an open/high resistance.
  2. Connect a test lamp between the appropriate trailer connector control circuit terminal and ground.
  3. Press and release the brake pedal, the test lamp should illuminate each time the brake pedal is pressed. If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the auxiliary fuse block. If the test lamp is always OFF, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the auxiliary fuse block.
  4. If all circuits test normal, replace the auxiliary fuse block.

Trailer Backup Lamp Circuit Malfunction

  1. Ignition OFF, disconnect the X1 harness connector at the auxiliary BCM.
  2. Test for less than 1 ohms between the low reference circuit terminal A1 and circuit terminal B7. If greater than the specified range, test the low reference terminal for a short to voltage or an open/high resistance.
  3. Connect a test lamp between the control circuit terminal B1 and ground.
  4. Command the Backup Lamps ON and OFF with a scan tool, the test lamp should turn ON and OFF while changing between the commanded states. If the test lamp is always OFF, test the control circuit for a short to ground or an open/high resistance. If the test lamp is always ON, test the control circuit for a short to voltage.
  5. Ignition OFF, connect the X1 harness connector and disconnect the X2 harness connector at the auxiliary BCM.
  6. Ignition ON, verify that a test lamp illuminates between the B+ circuit terminal B and ground. If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.
  7. Ignition OFF, connect the X2 harness connector at the auxiliary BCM.
  8. Connect a test lamp between the appropriate trailer connector circuit terminal and ground.
  9. Ignition ON, command the Backup Lamps ON and OFF with a scan tool. The test lamp should turn ON and OFF while changing between the commanded states. If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the auxiliary body control module. If the test lamp is always OFF, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the auxiliary BCM.
  10. If all circuits test normal, replace the auxiliary BCM.

Trailer Turn Signal Circuit Malfunction

  1. Ignition OFF, disconnect the appropriate Trailer Turn relay.
  2. Test for less than 1.0 ohms between the ground circuit terminal A1 and ground. If greater than the specified range, test the ground circuit for an open/high resistance.
  3. Ignition ON, verify that a test lamp does not illuminate between the control circuit terminal A2 and ground. If the test lamp illuminates, test the control circuit for a short to voltage.
  4. Verify that a test lamp illuminates between the B+ circuit terminal C1 and ground. If the test lamp does not illuminate, test the B+ circuit for an open/high resistance.
  5. Ignition ON, connect a 15 A fused jumper wire between the B+ circuit terminal C1 and the control circuit terminal A2. Verify that a test lamp illuminates between the appropriate trailer connector terminal and ground. If the test lamp does not illuminate, test the control circuit for an open/high resistance.
  6. Connect a test lamp between the control circuit terminal C2 and the ground circuit terminal A1.
  7. Command the LR Turn Signal or RR Turn Signal with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states. If the test lamp is always ON, test the control circuit for a short to voltage. If the test lamp is always OFF, test the control circuit for a short to ground or an open/high resistance.
  8. If all circuits test normal, test or replace the Trailer Turn relay.

Trailer Parking Lamp Circuit Malfunction

  1. Ignition OFF, disconnect the harness connector at the auxiliary fuse block
  2. Connect a test lamp between the control circuit terminal A and ground.
  3. Ignition ON, command the Parking Lamps ON and OFF with a scan tool, the test lamp should turn ON and OFF while changing between the commanded states. If the test lamp is always ON, test the control circuit for a short to voltage. If the test lamp is always OFF, test the control circuit for a short to ground or an open/high resistance.
  4. Connect a 7.5 A fused jumper wire between the control circuit terminal B and B+. Verify that a test lamp illuminates between the appropriate trailer connector control circuit terminal and ground. If the test lamp does not illuminate, test the control circuit for a short to ground or an open/high resistance.
  5. If all circuits test normal, replace the auxiliary fuse block.

Trailer Fog Lamp Circuit Malfunction

  1. Ignition OFF, disconnect the X2 harness connector at the auxiliary BCM.
  2. Ignition ON, verify that a test lamp illuminates between the B+ circuit terminal B and ground. If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.
  3. Ignition OFF, connect the X2 harness connector at the auxiliary BCM.
  4. Connect a test lamp between the appropriate trailer connector control circuit terminal and ground.
  5. Ignition ON, command the Trailer Fog Lamps ON and OFF with a scan tool. The test lamp should turn ON and OFF while changing between the commanded states. If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the auxiliary BCM. If the test lamp is always OFF, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the auxiliary BCM.
  6. If all circuits test normal, replace the auxiliary BCM.

Component Testing

Relay Test

  1. Ignition OFF, disconnect the appropriate relay.
  2. Test for 60-200 ohms between terminals 85 and 86. If not within the specified range, replace the relay.
  3. Test for infinite resistance between the following terminals: 30 and 86 30 and 86 30 and 86 30 and 86 If less than the specified value, replace the relay.
  4. Test for less than 2 ohms between terminals 30 and 87 A. If greater than the specified range, replace the relay.
  5. Install a 3 A fused jumper wire between relay terminal 85 and 12 V. Install a jumper wire between relay terminal 86 and ground. Test for less than 2 ohms between terminals 30 and 87. If greater than specified range, replace the relay.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Underhood Electrical Center or Junction Block Replacement»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-repair-instructions)
  2. «Relay Replacement (Attached to Wire Harness)»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-repair-instructions) or «Relay Replacement (Within an Electrical Center)»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-repair-instructions)
  3. «Control Module References»(/cadillac/cts/ii-2007-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM replacement, setup, and programming
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Body Control Module (BCM) 3 Fuse B+11
Body Control Module (BCM) 5 Fuse B+11
Body Control Module (BCM) 6 Fuse B+11
Hazard Switch Signal222
Tail Lamp Outage Detection Signal - Left444
Left Turn Signal Switch Signal333
Tail Lamp Outage Detection Signal - Right444
Right Turn Signal Switch Signal333
Left Front Turn Signal Lamp Control111
Right Front Turn Signal Lamp Control111
Left Rear Turn Lamp Control111
Right Rear Turn Lamp Control111
Hazard Switch Ground2
Left Rear Stop/Turn Lamp Ground1
Left Repeater Lamp Ground1
Right Repeater Lamp Ground1
Right Rear Stop/Turn Lamp Ground1
Turn Signal/Multifunction Switch Ground3
Turn Signal Lamp - LF Ground1
Turn Signal Lamp - RF Ground1
1. Turn Signal Lamps and/or Indicators Malfunction 2. Hazard Lamps Malfunction 3. Turn Signal Switch Malfunction 4. Tail Lamp Outage Detection Malfunction

Ground is applied at all times to the turn signal/multifunction switch. The turn signal lamps may only be activated with the ignition switch in the ON or START position. When the turn signal/multifunction switch is placed in either the TURN RIGHT or TURN LEFT position, ground is applied to the body control module (BCM) through either the right turn or left turn signal switch signal circuit. The BCM then applies a pulsating voltage to the front and rear turn signal lamps through there respective voltage supply circuits. When a turn signal request is received by the BCM, a serial data message is sent to the instrument panel cluster (IPC) requesting the respective turn signal indicator be pulsed ON and OFF.

The tail lamp outage detection circuits are low current B+ circuits supplied by the BCM. For purposes of testing, a test lamp connected between the outage detection circuit and ground will not illuminate due to low current.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition ON, observe the scan tool Right Turn Signal Switch and Left Turn Signal Switch parameters while cycling the turn signal switch between the right and left positions. The readings should change between Active and Inactive. If the parameters do not change between the selected states, refer to Turn Signal Switch Malfunction in «Circuit/System Testing»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system) .
  2. Ignition ON, observe the right and left turn signal lamps while cycling the turn signal switch between the right and left positions. Verify the turn signal lamps turn ON and OFF. If the turn signal lamps do not cycle between the selected states, refer to Turn Signal Lamps Malfunction in «Circuit/System Testing»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system) .
  3. Observe the left and right turn signal lamps and turn signal indicators on the IPC while activating the left and right turn signals. The left and right turn signal lamps and indicators should illuminate and flash at a normal rate when turned ON. If the left and right turn signal lamps and indictors illuminate but flash in a rapid manner, refer to Tail Lamp Outage Detection Malfunction in «Circuit/System Testing»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system) .
  4. Command the Display Test ON and OFF with a scan tool. The left and right turn signal indicators should turn ON and OFF when changing between the commanded states. If the left and right turn signal indicators illuminate during the test, replace the BCM. If the left and right turn signal indicators do not illuminate during the test or remain illuminated at all times, replace the instrument cluster.

Turn Signal Switch Malfunction

  1. Ignition OFF, disconnect the harness connector at the turn signal/multifunction switch.
  2. Ignition OFF, verify that a test lamp illuminates between B+ and the ground circuit terminal 1. If the test lamp does not illuminate, test the ground circuit for an open/high resistance.
  3. Ignition ON, verify the scan tool Left Turn Signal Switch parameter is Inactive. If not the specified value, test the signal circuit terminal 2 for a short to ground. If the circuit tests normal, replace the BCM.
  4. Verify the scan tool Right Turn Signal Switch parameter is Inactive. If not the specified value, test the signal circuit terminal 3 for a short to ground. If the circuit tests normal, replace the BCM.
  5. Install a 3 A fused jumper wire between the signal circuit terminal 2 and ground. Verify the scan tool Left Turn Signal Switch parameter is Active. If not the specified value, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the BCM.
  6. Install a 3 A fused jumper wire between the signal circuit terminal 3 and ground. Verify the scan tool Right Turn Signal Switch parameter is Active. If not the specified value, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the BCM.
  7. If all circuits test normal, test or replace the turn signal/multifunction switch.

Turn Signal Lamps Malfunction

  1. Ignition OFF, disconnect the X4 harness connector at the BCM.
  2. Verify that a test lamp illuminates between the B+ circuit terminal 2 and ground. If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.
  3. Verify that a test lamp illuminates between the B+ circuit terminal 1 and ground. If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.
  4. Verify that a test lamp illuminates between the B+ circuit terminal 3 and ground. If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.
  5. Ignition OFF, connect the X4 harness connector at the BCM.
  6. Disconnect the harness connector at the inoperative turn signal lamp.
  7. Ignition OFF, exterior lamps OFF, test for less than 5 ohms between the appropriate ground circuit terminal listed below and ground. Left front turn signal ground terminal B Right front turn signal ground terminal B Left rear turn signal ground terminal C - North America Right rear turn signal ground terminal C - North America Left rear turn signal ground terminal H - European Right rear turn signal ground terminal H - European Left repeater ground terminal 2 - European Right repeater ground terminal 2 - European If greater than the specified range, test the ground circuit for an open/high resistance.
  8. Connect a test lamp between the appropriate control circuit terminal listed below and ground. Left front turn signal control terminal A Right front turn signal control terminal A Left rear turn signal control terminal B - North America Right rear turn signal control terminal B - North America Left rear turn signal control terminal G - European Right rear turn signal control terminal G - European Left repeater control terminal 1 - European Right repeater control terminal 1 - European
  9. Command the appropriate Turn Signal Lamp ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states. If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the BCM. If the test lamp is always OFF, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM.
  10. If all circuits test normal, replace the appropriate turn signal lamp assembly.

Tail Lamp Outage Detection Malfunction

  1. Ignition OFF, disconnect the harness connector at the appropriate rear tail lamp assembly.
  2. Ignition ON, test for B+ between the signal circuit terminal D and ground. If less than the specified value, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM.
  3. Ignition ON, verify that a test lamp does not illuminate between the signal circuit terminal D and ground. If the test lamp illuminates, test the signal circuit for a short to voltage. If the circuit tests normal, replace the BCM.
  4. If all circuits test normal, test or replace the tail lamp assembly.

Tail Lamp Assembly

  1. Ignition OFF, disconnect the harness connector at the appropriate rear tail lamp assembly.
  2. Test for infinite resistance between terminal D and terminal C at the tail lamp assembly. If not the specified value, replace the tail lamp assembly.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Tail Lamp Replacement (Sedan, V-Series)»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system) or «Tail Lamp Replacement (Wagon)»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system)
  2. «Parking and Turn Signal Lamp Bulb Replacement»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system)
  3. «Turn Signal Multifunction Switch Replacement»(/cadillac/cts/ii-2007-2014/remont/steering-column-switches/#steering-wheel-steering-column)
  4. «Front Side Turn Signal Lamp Replacement»(/cadillac/cts/ii-2007-2014/remont/exterior-lights/#lighting-system)
  5. «Control Module References»(/cadillac/cts/ii-2007-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM or IPC replacement, setup, and programming

Brake Pedal Position Sensor Calibration

Note. Brake system does not use a brake switch, stoplight switch or brakelight switch. System uses a Brake Pedal Position Sensor to control these functions.

Calibration Criteria

IMPORTANTDo not apply the brake pedal during the brake pedal position sensor calibration procedure. Any movement of the brake pedal during this procedure will cause the calibration procedure to fail. If this occurs, the brake pedal position sensor (BPPS) calibration must be repeated.

Brake pedal position sensor calibration must be performed after the brake pedal position sensor or body control module (BCM) have been serviced. The calibration procedure will set the brake pedal position sensor home value. This value is used by the BCM to determine the action of the driver applying the brake system and to provide this information to the vehicle subsystems via the GMLAN communication bus.

Calibration Procedure

  1. Apply the parking brake.
  2. Place the transmission in the PARK position.
  3. Install a scan tool.
  4. Clear all BCM DTCs before proceeding.
  5. Navigate to the Vehicle Control Systems menu.
  6. Select Module Setup menu item.
  7. Select BCM menu item.
  8. Select the BPP Sensor Calibration procedure and follow the directions displayed on the screen.

Brake Pedal Position Sensor Replacement

Note. Brake system does not use a brake switch, stoplight switch or brakelight switch. System uses a Brake Pedal Position Sensor to control these functions.

Scheme 22

Scheme 22: Brake Pedal Position Sensor Replacement
Scheme 22: Brake Pedal Position Sensor Replacement
CalloutComponent Name
Preliminary Procedure: Remove the driver side knee bolster. Refer to Driver Knee Bolster Replacement (Left Hand Drive) or Driver Knee Bolster Replacement (Right Hand Drive) .
1Brake Pedal Position Sensor Bolt CAUTION: Refer to Fastener Caution . Procedure: Remove the sensor bolt. Tighten: 9 N.m (80 lb in)
2Brake Pedal Position Sensor Procedure Disconnect the electrical connector. Pull the sensor away from the bracket. Recalibrate the brake pedal position sensor. Refer to Brake Pedal Position Sensor Calibration .
CAUTION
Refer to Fastener Caution .

Scheme 23

Scheme 23: Instrument Panel Lamp Dimmer Switch Replacement
Scheme 23: Instrument Panel Lamp Dimmer Switch Replacement
CalloutComponent Name
1Instrument Panel Outer Air Outlet Deflector Assembly. Refer to Instrument Panel Outer Air Outlet Deflector Replacement - Left Side .
2Instrument Panel Lamp Dimmer Switch Assembly Procedure: Unsnap the dimmer switch assembly from the outer air deflector.

Scheme 24

Scheme 24: Headlamp Automatic Control Ambient Light Sensor Replacement
Scheme 24: Headlamp Automatic Control Ambient Light Sensor Replacement
CalloutComponent Name
Preliminary Procedure: Remove the defroster grille. Refer to Windshield Defroster Nozzle Grille Replacement (Left Hand Drive) or Windshield Defroster Nozzle Grille Replacement (Right Hand Drive) .
1Headlamp Auto Control Ambient Light Sensor Procedure Disconnect the electrical connector. Twist the sensor counterclockwise.

Scheme 25

Scheme 25: Courtesy Lamp Replacement (Wagon)
Scheme 25: Courtesy Lamp Replacement (Wagon)
CalloutComponent Name
1Courtesy Lamp Procedure Depress the integral four tabs and use a flat-bladed tool to remove the courtesy lamp from the roof console. Disconnect the electrical connector.

Scheme 26

Scheme 26: Door Lamp Replacement
Scheme 26: Door Lamp Replacement
CalloutComponent Name
Preliminary Procedure: Remove the front side door trim panel. Refer to Front Side Door Trim Panel Replacement .
1Door Lamp Procedure: Remove the electrical connectors.

Scheme 27

Scheme 27: Door Courtesy Lamp and Reflector Replacement
Scheme 27: Door Courtesy Lamp and Reflector Replacement
CalloutComponent Name
1Door Courtesy Lamp and Reflector Procedure Depress the clips and use a flat-bladed tool to remove the door courtesy lamp from the door trim panel. Disconnect the electrical connectors.

Scheme 28

Scheme 28: Instrument Panel Flood Lamp Replacement - Left Side
Scheme 28: Instrument Panel Flood Lamp Replacement - Left Side
CalloutComponent Name
1Instrument Panel Outer Air Outlet Deflector Assembly. Refer to Instrument Panel Outer Air Outlet Deflector Replacement - Left Side .
2Instrument Panel Flood Lamp Assembly Procedure: Unsnap the flood lamp assembly from the outer air deflector.

Scheme 29

Scheme 29: Instrument Panel Flood Lamp Replacement - Right Side
Scheme 29: Instrument Panel Flood Lamp Replacement - Right Side
CalloutComponent Name
Preliminary Procedure Remove the right instrument panel trim plate applique. Refer to Instrument Panel Trim Plate Applique Replacement - Right Side (Left Hand Drive) or Instrument Panel Trim Plate Applique Replacement - Right Side (Right Hand Drive ) . Remove the instrument panel compartment assembly. Refer to Instrument Panel Compartment Replacement (Left Hand Drive) or Instrument Panel Compartment Replacement (Right Hand Drive) .
1Instrument Panel Flood Lamp Assembly Procedure Note the routing of the wiring through the instrument panel assembly to ensure proper reinstallation. Disconnect the electrical connector. Unsnap the flood lamp assembly from the instrument panel.

Scheme 30

Scheme 30: Instrument Panel Courtesy Lamp Bulb Replacement
Scheme 30: Instrument Panel Courtesy Lamp Bulb Replacement
CalloutComponent Name
1Courtesy Lamp Bulb Procedure: Pull the bulb out straight.

Scheme 31

Scheme 31: Overhead Console Reading Lamp and Bulb Replacement
Scheme 31: Overhead Console Reading Lamp and Bulb Replacement
CalloutComponent Name
Preliminary Procedure: Remove the roof console. Refer to Roof Console Replacement .
1Overhead Console Reading Lamp Screw (Qty: 2) CAUTION: Refer to Fastener Caution . Tighten: 2 N.m (18 lb in)
2Overhead Console Reading Lamp Housing
3Overhead Console Reading Lamp Bulb Procedure: Pull the bulb straight out.
CAUTION
Refer to Fastener Caution .

Scheme 32

Scheme 32: Luminescent Lamp Replacement - Driver or Passenger Seat
Scheme 32: Luminescent Lamp Replacement - Driver or Passenger Seat
CalloutComponent Name
1Luminescent Lamp - Front Seat Procedure Disconnect the electrical connector. Squeeze the bottom tabs together and push up to remove.

Scheme 33

Scheme 33: Sunshade Illuminated Mirror Lamp Bulb Replacement
Scheme 33: Sunshade Illuminated Mirror Lamp Bulb Replacement
CalloutComponent Name
1Lamp Lens Procedure: Use a flat-bladed tool and detach the lens.
2Lamp Bulb

Scheme 34

Scheme 34: Headlamp Ballast Replacement (Sedan)
Scheme 34: Headlamp Ballast Replacement (Sedan)
CalloutComponent Name
WARNING: The high intensity discharge system produces high voltage and current. In order to reduce the risk of severe shocks and burns, the battery negative cable must be disconnected any time service work is being performed on or around the high intensity discharge system. WARNING: The high intensity discharge system produces high voltage and current. To reduce the risk of severe shocks and burns: Never open the high intensity discharge system ballast or the arc tube assembly starter. Never probe between the high intensity discharge system ballast output connector and the arc tube assembly. Preliminary Procedure: Remove the headlamp capsule. Refer to Headlamp Capsule Replacement .
1Ballast Assembly Screw (Qty: 3) Tip: Hand tighten the screws only, no torque required.
2Ballast Assembly Tip: Remove the ballast assembly and inspect the sealing gasket prior to installing the new ballast assembly.
WARNING
The high intensity discharge system produces high voltage and current. In order to reduce the risk of severe shocks and burns, the battery negative cable must be disconnected any time service work is being performed on or around the high intensity discharge system.
WARNING
The high intensity discharge system produces high voltage and current. To reduce the risk of severe shocks and burns: Never open the high intensity discharge system ballast or the arc tube assembly starter. Never probe between the high intensity discharge system ballast output connector and the arc tube assembly.

Headlamp Ballast Replacement (European)

CalloutComponent Name
WARNING: The high intensity discharge system produces high voltage and current. In order to reduce the risk of severe shocks and burns, the battery negative cable must be disconnected any time service work is being performed on or around the high intensity discharge system. WARNING: The high intensity discharge system produces high voltage and current. To reduce the risk of severe shocks and burns: Never open the high intensity discharge system ballast or the arc tube assembly starter. Never probe between the high intensity discharge system ballast output connector and the arc tube assembly. Preliminary Procedure: Remove the headlamp capsule. Refer to Headlamp Capsule Replacement .
1Ballast Assembly Screw (Qty: 3) Hand tighten the screws only, no torque required.
2Ballast Assembly Tip: Remove the ballast assembly and inspect the sealing gasket prior to installing the new ballast assembly.
WARNING
The high intensity discharge system produces high voltage and current. In order to reduce the risk of severe shocks and burns, the battery negative cable must be disconnected any time service work is being performed on or around the high intensity discharge system.
WARNING
The high intensity discharge system produces high voltage and current. To reduce the risk of severe shocks and burns: Never open the high intensity discharge system ballast or the arc tube assembly starter. Never probe between the high intensity discharge system ballast output connector and the arc tube assembly.

Scheme 35

Scheme 35: Headlamp Assembly or Headlamp Bulb and/or Cornering, Sidemarker, Park, Turn Signal Bulb Replacement
Scheme 35: Headlamp Assembly or Headlamp Bulb and/or Cornering, Sidemarker, Park, Turn Signal Bulb Replacement
CalloutComponent Name
WARNING: The high intensity discharge system produces high voltage and current. In order to reduce the risk of severe shocks and burns, the battery negative cable must be disconnected any time service work is being performed on or around the high intensity discharge system. WARNING: The high intensity discharge system produces high voltage and current. To reduce the risk of severe shocks and burns: Never open the high intensity discharge system ballast or the arc tube assembly starter. Never probe between the high intensity discharge system ballast output connector and the arc tube assembly. Preliminary Procedure: Remove the headlamp capsule. Refer to Headlamp Capsule Replacement .
1Accessory Cap Screw (Qty: 3) Tip: Hand tighten only, the accessory cap screws.
2Accessory Cap Tip: Inspect and ensure the accessory cap seal is properly seated prior to installing the accessory cap cover.
3Turn Signal Lamp Bulb WARNING: Refer to Halogen Bulb Warning . Procedure Disconnect the electrical connector from the bulb socket. Rotate the bulb socket counter-clockwise and remove from the headlamp assembly. Replace the bulb as needed.
4Daytime Running Lamp Bulb (DRL) WARNING: Refer to Halogen Bulb Warning . Procedure Disconnect the electrical connector from the bulb socket. Pinch the bulb socket locking tabs and pull the bulb socket from the headlamp assembly. Replace the bulb as needed.
5Accessory Cap Screw (Qty: 3) Tip: Hand tighten only, the accessory cap screws.
6Accessory Cap Tip: Inspect and ensure the seal is properly seated prior to installing the accessory cap.
7Headlamp Bulb with Ballast WARNING: Refer to Halogen Bulb Warning . Procedure Rotate counter-clockwise and unlock the bulb ballast assembly and remove from the headlamp composite. Disconnect the electrical connector from the bulb ballast.
WARNING
The high intensity discharge system produces high voltage and current. In order to reduce the risk of severe shocks and burns, the battery negative cable must be disconnected any time service work is being performed on or around the high intensity discharge system.
WARNING
The high intensity discharge system produces high voltage and current. To reduce the risk of severe shocks and burns: Never open the high intensity discharge system ballast or the arc tube assembly starter. Never probe between the high intensity discharge system ballast output connector and the arc tube assembly.
WARNING
Refer to Halogen Bulb Warning .
WARNING
Refer to Halogen Bulb Warning .
WARNING
Refer to Halogen Bulb Warning .

Scheme 36

Scheme 36: Headlamp Assembly or Headlamp Bulb and/or Cornering, Sidemarker, Park, Turn Signal Bulb Replacement
Scheme 36: Headlamp Assembly or Headlamp Bulb and/or Cornering, Sidemarker, Park, Turn Signal Bulb Replacement
CalloutComponent Name
WARNING: The high intensity discharge system produces high voltage and current. In order to reduce the risk of severe shocks and burns, the battery negative cable must be disconnected any time service work is being performed on or around the high intensity discharge system. WARNING: The high intensity discharge system produces high voltage and current. To reduce the risk of severe shocks and burns: Never open the high intensity discharge system ballast or the arc tube assembly starter. Never probe between the high intensity discharge system ballast output connector and the arc tube assembly. Preliminary Procedure: Remove the headlamp capsule. Refer to Headlamp Capsule Replacement .
1Accessory Cap Screw (Qty: 3) Tip: Hand tighten only, the accessory cap screws.
2Accessory Cap Tip: Inspect and ensure the accessory cap seal is properly seated prior to installing the accessory cap cover.
3Directional Bulb WARNING: Refer to Halogen Bulb Warning . Procedure Rotate the bulb socket from the headlamp assembly. Disconnect the electrical connector from the bulb socket.
4Accessory Cap Screw (Qty: 3) Tip: Hand tighten only, the accessory cap screws.
5Accessory Cap Tip: Inspect and ensure the seal is properly seated prior to installing the accessory cap.
6Headlamp Bulb with HID Ballast WARNING: Refer to Halogen Bulb Warning . Procedure Rotate counter-clockwise and unlock the bulb ballast assembly and remove from the headlamp composite. Disconnect the electrical connector from the bulb HID ballast.
WARNING
The high intensity discharge system produces high voltage and current. In order to reduce the risk of severe shocks and burns, the battery negative cable must be disconnected any time service work is being performed on or around the high intensity discharge system.
WARNING
The high intensity discharge system produces high voltage and current. To reduce the risk of severe shocks and burns: Never open the high intensity discharge system ballast or the arc tube assembly starter. Never probe between the high intensity discharge system ballast output connector and the arc tube assembly.
WARNING
Refer to Halogen Bulb Warning .
WARNING
Refer to Halogen Bulb Warning .

Headlamp Assembly or Headlamp Bulb and/or Cornering, Sidemarker, Park, Turn Signal Bulb Replacement (TT8)

CalloutComponent Name
WARNING: The high intensity discharge system produces high voltage and current. In order to reduce the risk of severe shocks and burns, the battery negative cable must be disconnected any time service work is being performed on or around the high intensity discharge system. WARNING: The high intensity discharge system produces high voltage and current. To reduce the risk of severe shocks and burns: Never open the high intensity discharge system ballast or the arc tube assembly starter. Never probe between the high intensity discharge system ballast output connector and the arc tube assembly. Preliminary Procedure: Remove the headlamp capsule. Refer to Headlamp Capsule Replacement .
1Accessory Cap Screw (Qty: 3) Tip: Hand tighten only, the accessory cap screws.
2Accessory Cap Tip: Inspect and ensure the accessory cap seal is properly seated prior to installing the accessory cap cover.
3Directional Bulb WARNING: Refer to Halogen Bulb Warning . Procedure Rotate the bulb socket from the headlamp assembly. Disconnect the electrical connector from the bulb socket.
4Accessory Cap Screw (Qty: 3) Tip: Hand tighten only, the accessory cap screws.
5Accessory Cap Tip: Inspect and ensure the seal is properly seated prior to installing the accessory cap.
6Headlamp Bulb with HID Ballast WARNING: Refer to Halogen Bulb Warning . Procedure Rotate counter-clockwise and unlock the bulb ballast assembly and remove from the headlamp composite. Disconnect the electrical connector from the bulb HID ballast.
WARNING
The high intensity discharge system produces high voltage and current. In order to reduce the risk of severe shocks and burns, the battery negative cable must be disconnected any time service work is being performed on or around the high intensity discharge system.
WARNING
The high intensity discharge system produces high voltage and current. To reduce the risk of severe shocks and burns: Never open the high intensity discharge system ballast or the arc tube assembly starter. Never probe between the high intensity discharge system ballast output connector and the arc tube assembly.
WARNING
Refer to Halogen Bulb Warning .
WARNING
Refer to Halogen Bulb Warning .

Scheme 37

Scheme 37: Headlamp Assembly or Headlamp Bulb and/or Cornering, Sidemarker, Park, Turn Signal Bulb Replacement
Scheme 37: Headlamp Assembly or Headlamp Bulb and/or Cornering, Sidemarker, Park, Turn Signal Bulb Replacement
CalloutComponent Name
Preliminary Procedure: Remove the headlamp capsule. Refer to Headlamp Capsule Replacement .
1Accessory Cap Screw Tip: Hand tighten only, the accessory cap screws.
2Accessory Cap Tip: Inspect and ensure the seal is properly seated prior to installing the cap.
3Low Beam Bulb WARNING: Refer to Halogen Bulb Warning . Procedure Disconnect the electrical connector from the bulb socket. Turn the bulb socket counter-clockwise and remove.
4Accessory Cap Screw Tip: Hand tighten only, the accessory cap screws.
5Accessory Cap Tip: Inspect and ensure the seal is properly seated prior to installing the cap.
6High Beam Bulb WARNING: Refer to Halogen Bulb Warning . Procedure Disconnect the electrical connector from the bulb socket. Turn the bulb socket counter-clockwise and remove.
WARNING
Refer to Halogen Bulb Warning .
WARNING
Refer to Halogen Bulb Warning .

Scheme 38

Scheme 38: Headlamp Capsule Replacement
Scheme 38: Headlamp Capsule Replacement
CalloutComponent Name
WARNING: The high intensity discharge system produces high voltage and current. In order to reduce the risk of severe shocks and burns, the battery negative cable must be disconnected any time service work is being performed on or around the high intensity discharge system. WARNING: The high intensity discharge system produces high voltage and current. To reduce the risk of severe shocks and burns: Never open the high intensity discharge system ballast or the arc tube assembly starter. Never probe between the high intensity discharge system ballast output connector and the arc tube assembly. Preliminary Procedure Open and support the hood. Remove the front bumper fascia. Refer to Front Bumper Fascia Replacement . Disconnect the headlamp electrical connector at the base of the headlamp assembly.
1Headlamp Capsule Assembly Bolt (Qty: 2) CAUTION: Refer to Fastener Caution . Tighten: 6 N.m (53 lb in)
2Headlamp Capsule Assembly Nut Tighten: 6 N.m (53 lb in)
3Headlamp Capsule Assembly Tip: Carefully move the headlamp capsule assembly upward and outward in order to remove.
WARNING
The high intensity discharge system produces high voltage and current. In order to reduce the risk of severe shocks and burns, the battery negative cable must be disconnected any time service work is being performed on or around the high intensity discharge system.
WARNING
The high intensity discharge system produces high voltage and current. To reduce the risk of severe shocks and burns: Never open the high intensity discharge system ballast or the arc tube assembly starter. Never probe between the high intensity discharge system ballast output connector and the arc tube assembly.
CAUTION
Refer to Fastener Caution .

Scheme 39

Scheme 39: Headlamp Bracket Replacement
Scheme 39: Headlamp Bracket Replacement
CalloutComponent Name
Preliminary Procedure: Remove the headlamp capsule. Refer to Headlamp Capsule Replacement .
1Headlamp Bracket Screw (Qty: 3) Procedure: Hand tighten the screws only, in order to secure the bracket to the bottom of the headlamp assembly.
2Headlamp Bracket

Aiming Headlamps (Visual Aim)

IMPORTANTSome state and local laws specify requirements for headlamp aim. All of these laws must be complied with when performing any headlamp aiming operations.

Headlamp aim should be checked

  1. When a new headlamp capsule is installed.
  2. If service or repairs to the front end area have (or may have) disturbed the headlamps or their mounting.
  3. Suspension components have been replaced or repaired.
  1. The area will consist of a level surface large enough to allow for a vehicle and an additional 7.62 m (25 ft) measured from face of lamps to the front of the aiming screen.
  2. The screen will be 1.52 m (5 ft) high x 3.66 m (12 ft) wide with a matte white surface well shaded from extraneous light, and properly adjusted to the floor on which the vehicle stands. Provisions may be made for moving the screen so it can be aligned parallel with the vehicle.
  3. The screen shall be provided with a fixed vertical centerline, 2 laterally adjustable vertical tapes, and 1 vertically adjustable horizontal tape.
  4. If a regular commercial aiming screen is not available, the screen may consist of a vertical wall having a clear uninterrupted area approximately 1.83 m (6 ft) high and 3.66 m (12 ft) wide. The surface should be finished with a washable non-gloss white paint.
  5. After the aiming screen has been set up in its permanent location, it is necessary to paint a reference line on the floor directly under the lens of the lamps to indicate the proper location of the headlamps when they are being aimed: Distance between headlamps (1) Center line of screen (2) Adjustable vertical pointer (3) Adjustable horizontal tape (4) Diagram of light screen (5) Vertical center line ahead of right headlamp pointer position (6) 7.62 m (25 ft) (7) Car centerline axis (8)

Prior to aiming the headlamps, the following steps must be taken

  1. Remove any snow, ice or mud from the vehicle.
  2. The vehicle must have a full tank of gas.
  3. Stop all other work on the vehicle.
  4. If any service has been performed on the vehicle, make sure that all of the components are back in their original place.
  5. The vehicle must be on a level surface.
  6. The vehicle left tires must be aligned with the reference line extending from the screen with the headlamps aligned with the vertical reference line (2).
  7. Do not load any cargo in the vehicle.
  8. The vehicle must contain 1 person or 72.56 kg (160 lb) on the driver's seat.
  9. Inflate the tires to the proper pressure.
  10. Simulate the vehicle loads if the intended use of the vehicle is for hauling heavy loads or towing a trailer.
  11. Rock the vehicle in order to stabilize the suspension.
  12. Turn ON the headlamps to low beam and observe the left and the top edges of the high intensity zone on the screen. The edges of the high intensity zone should fall within the specifications.

Headlamp Aiming Procedure

  1. Open the hood.
  2. Measure from the floor to the center of the headlamp bulb, some headlamps have an aim dot marked on the headlamp lens.
  3. At the screen, measure from the floor and place the horizontal tape at the measured distance.
  4. Measure from the reference line on the floor to the left headlamp bulb centerline.
  5. At the screen, measure from the reference line and place the vertical tape at the measured distance.
  6. Measure from the reference line on the floor to the right headlamp bulb centerline.
  7. At the screen, measure from the reference line and place the vertical tape at the measured distance.
  8. Turn on the low beam headlamps and block the light from projecting onto the screen from the passenger side headlamp.
  9. Adjust the vertical aim of the headlamps to the specifications required by the state and the local authorities, or as shown in step number 8.
  10. Rotate the headlamp adjuster to change the vertical aim of the headlamp.
  11. Repeat the aiming procedure for the passenger side headlamp while blocking the light from projecting onto the screen from the driver side headlamp.
  12. Close the hood.

Removal Procedure

  1. Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#general-information) .
  2. Remove the front tire and wheel assembly. Refer to «Tire and Wheel Removal and Installation»(/cadillac/cts/ii-2007-2014/remont/wheel-tire-system/#tires-and-wheels__tire-and-wheel-removal-and-installation) .
  3. Disconnect the electrical connector (1).
  4. Disconnect the ball and socket (1) from upper control arm.
  5. Loosen the clinch nut (2) from the stud.
  6. Rotate and remove the sensor from the wheelhouse panel.

Installation Procedure

  1. Position and rotate the sensor (1) and the locking tab into the holes in the wheelhouse panel.
  2. Secure the clinch nut (2) on the stud to the wheelhouse panel and tighten to 9 N.m (80 lb in).
  3. Lock the ball socket (1) to upper control arm ball stud.
  4. Connect the electrical connector (1) to the sensor assembly.
  5. Install the tire and wheel assembly. Refer to «Tire and Wheel Removal and Installation»(/cadillac/cts/ii-2007-2014/remont/wheel-tire-system/#tires-and-wheels__tire-and-wheel-removal-and-installation) .
  6. Lower the vehicle.
  7. Set up and program the headlamp control module. Refer to «Control Module References»(/cadillac/cts/ii-2007-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) .
  1. Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#general-information) .
  2. Remove the right rear tire and wheel assembly. Refer to «Tire and Wheel Removal and Installation»(/cadillac/cts/ii-2007-2014/remont/wheel-tire-system/#tires-and-wheels__tire-and-wheel-removal-and-installation) .
  3. Disconnect electrical connector (2).
  4. Disconnect the ball and socket (3) from vehicle.
  5. Loosen the clinch nut (1) from the sensor.
  6. Remove the sensor from the vehicle.
  1. Position the sensor (3) to the vehicle and engage the locking tab to the wheelhouse bracket.
  2. Secure the clinch nut (1) in order to secure the sensor (4) to the vehicle. Tighten: Tighten 9 N.m (80 lb in).
  3. Secure the ball and socket (3) to sensor (4).
  4. Connect electrical connector (2) to the sensor (4).
  5. Install the right tire and wheel assembly. Refer to «Tire and Wheel Removal and Installation»(/cadillac/cts/ii-2007-2014/remont/wheel-tire-system/#tires-and-wheels__tire-and-wheel-removal-and-installation) .
  6. Lower the vehicle.
  7. Set up and program the headlamp control module. Refer to «Control Module References»(/cadillac/cts/ii-2007-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) .

Scheme 40

Scheme 40: Headlamp Control Module Replacement
Scheme 40: Headlamp Control Module Replacement
CalloutComponent Name
Preliminary Procedure: Remove the underhood electrical center. Refer to Underhood Electrical Center or Junction Block Replacement .
1Headlamp Control Module Procedure Disconnect the electrical connectors. Unsnap the module from the bracket. Refer to Control Module References for programming and set up procedures.

Scheme 41

Scheme 41: Front Fog Lamp Replacement (Sedan)
Scheme 41: Front Fog Lamp Replacement (Sedan)
CalloutComponent Name
Preliminary Procedures Remove either the LF or RF wheelhouse extension. Refer to Wheelhouse Extension Replacement . Disconnect the fog lamp bulb socket electrical connector.
1Front Fog Lamp Adjuster Screw Procedure Remove the adjuster screw from the fog lamp bracket and lamp assembly. Count the number of turns when removing the adjuster screw for a reference upon installation. Aim the fog lamps after installation. Refer to Fog Lamp Aiming .
2Front Fog Lamp Screw (Qty: 2) CAUTION: Refer to Fastener Caution . Tighten: 2 N.m (18 lb in)
3Front Fog Lamp Assembly Tip: Remove the lamp assembly from the fog lamp bracket.
4Front Fog Lamp Bulb Socket WARNING: Refer to Halogen Bulb Warning . Tip: Turn the bulb socket counterclockwise and remove from the lamp assembly.
CAUTION
Refer to Fastener Caution .
WARNING
Refer to Halogen Bulb Warning .

Scheme 42

Scheme 42: Front Fog Lamp Replacement (V-Series)
Scheme 42: Front Fog Lamp Replacement (V-Series)
CalloutComponent Name
Preliminary Procedures Remove either the LF or RF wheelhouse extension. Refer to Wheelhouse Extension Replacement . Disconnect the fog lamp bulb socket electrical connector.
1Front Fog Lamp Screw (Qty: 2)
2Front Fog Lamp Adjuster Screw Tip: Remove and discard the screw.
3Front Fog Lamp Projector Procedure Remove and discard the fog lamp projector. The fog lamp assembly is serviced as one unit. Position the new fog lamp locking ring to the tabs on the front bumper fascia and apply inward pressure to secure the new fog lamp to the front bumper fascia. Ensure all tabs are secure on the locking ring. Aim the fog lamps after the new fog lamps have been installed. Refer to Fog Lamp Aiming .
4Front Fog Lamp Locking Ring Tip: Using a small flat-bladed tool, release the locking ring from the tabs on the front bumper fascia and discard.

Scheme 43

Scheme 43: Front Fog Lamp Bulb Replacement
Scheme 43: Front Fog Lamp Bulb Replacement
CalloutComponent Name
Preliminary Procedures Remove either the LF or RF wheelhouse liner extension. Refer to Wheelhouse Extension Replacement . Disconnect the fog lamp bulb socket electrical connector.
1Front Fog Lamp Bulb Socket WARNING: Refer to Halogen Bulb Warning . Tip: Turn the bulb socket counterclockwise and remove from the lamp assembly.
WARNING
Refer to Halogen Bulb Warning .

Scheme 44

Scheme 44: Rear Fog Lamp Replacement (T79)
Scheme 44: Rear Fog Lamp Replacement (T79)
CalloutComponent Name
1Rear Fascia Insert Retainer (Qty: 4) Procedure Release only two retainers from one lamp assembly if only servicing one lamp. Rotate the fog lamp from the retainer tabs on the rear bumper fascia insert in order to remove.
2Fog Lamp Bracket Screw (Qty 4) CAUTION: Refer to Fastener Caution . Tip: Remove only two screws if servicing one lamp assembly. Tighten: 1.5 N.m (13 lb in)
3Rear Fog Lamp Bracket
4Rear Fog Lamp Assembly Tip: Disconnect the electrical connector from the main harness on the lamp being serviced.
CAUTION
Refer to Fastener Caution .

Adjustment Procedure

Proper road illumination and safety require the fog lamps to be aimed. The front fog lamp aim should be checked when a new front fog lamp assembly is installed, or if any service repairs have been performed to the vehicle which disturb the front fog lamp mounting or the vehicle ride height.

There are no horizontal adjustments for aiming the front fog lamp assemblies on this vehicle.

  1. To ensure accurate vertical front fog lamp aiming, first perform the following steps to prepare the vehicle. Make sure that all the components are in place on the vehicle, the tires are properly inflated, and there is not any mud or snow clinging to the vehicle. Stop all other operations of work on the vehicle. Make sure the fuel level is 1/2 full or more. Jounce the vehicle to settle the suspension. Place the vehicle on a level surface 7.6 m (25 ft) from the target screen. Measure the distance from the floor to the center of the fog lamp (5). Using this measurement, mark the horizontal centerline of the fog lamp (1) on the target screen directly in front of the vehicle. Start the vehicle in order to level the electronic suspension. Turn off the vehicle.
  2. Turn the front fog lamps ON.
  3. Through the opening in the front bumper fascia above the fog lamp is the fog lamp vertical adjusting screw, as indicated.
  4. Adjust the fog lamp up or down until the top edge of the high intensity zone on the screen is 102 mm (4 in) below the horizontal centerline.
  5. Turn OFF the front fog lamps.

Scheme 45

Scheme 45: Front Position Lamp Bulb Replacement
Scheme 45: Front Position Lamp Bulb Replacement
CalloutComponent Name
Preliminary Procedure: Remove the headlamp capsule. Refer to Headlamp Capsule Replacement .
1Accessory Cap Screw (Qty: 3) Tip: Hand tighten only, the accessory cap screws.
2Accessory Cap Tip: Inspect and ensure the accessory cap seal is properly seated prior to installing the accessory cap cover.
3Position Lamp Bulb Socket WARNING: Refer to Halogen Bulb Warning . Procedure Pinch the tabs on the position lamp bulb socket and pull the bulb socket from the headlamp assembly. Remove and replace the bulb.
4Park Signal Lamp Bulb Procedure Pinch the tabs on the bulb socket and pull the bulb socket from the headlamp assembly. Disconnect the electrical connector from the bulb socket. Remove and replace the bulb.
WARNING
Refer to Halogen Bulb Warning .

Scheme 46

Scheme 46: Front Side Turn Signal Lamp Replacement
Scheme 46: Front Side Turn Signal Lamp Replacement
CalloutComponent Name
Preliminary Procedure: Apply two layers of masking tape to the rear edge of the lamp assembly in order to protect the painted surface when removing the lamp from the fender.
1Front Side Turn Signal Lamp Procedure Using a small flat-bladed tool, depress the locking tab at the rear edge of the turn signal lamp assembly. Pull the lamp outward away from the fender. Disconnect the electrical connector to remove the lamp assembly. Rotate the bulb socket from the lamp. Replace the bulb as needed.

Scheme 47

Scheme 47: Parking and Turn Signal Lamp Bulb Replacement
Scheme 47: Parking and Turn Signal Lamp Bulb Replacement
CalloutComponent Name
Preliminary Procedure: Remove the headlamp capsule. Refer to Headlamp Capsule Replacement .
1Accessory Cap Screw (Qty: 3) Tip: Hand tighten only, the accessory cap screws.
2Accessory Cap Tip: Inspect and ensure the accessory cap seal is properly seated prior to installing the accessory cap cover.
3Turn Signal Lamp Bulb WARNING: Refer to Halogen Bulb Warning . Procedure Pinch the tabs on the bulb socket and pull the bulb socket from the headlamp assembly. Disconnect the electrical connector from the bulb socket. Remove and replace the bulb.
4Park Signal Lamp Bulb Procedure Pinch the tabs on the bulb socket and pull the bulb socket from the headlamp assembly. Disconnect the electrical connector from the bulb socket. Remove and replace the bulb.
WARNING
Refer to Halogen Bulb Warning .

Scheme 48

Scheme 48: High Mount Stop Lamp Replacement (Sedan, V-Series)
Scheme 48: High Mount Stop Lamp Replacement (Sedan, V-Series)
CalloutComponent Name
Preliminary Procedure Open the rear compartment lid. Remove the rear compartment lid inner panel trim. Refer to Rear Compartment Lid Inner Panel Trim Replacement (Sedan) .
1High Mount Stop Lamp Nut (Qty: 4) CAUTION: Refer to Fastener Caution . Tighten: 4 N.m (35 lb in)
2High Mount Stop Lamp Retainer (Qty: 2) Tip: Squeeze the retainer tabs inward and push the lamp assembly tabs outward in order to remove the lamp assembly from the rear compartment lid.
3High Mount Stop Lamp Electrical Connector
4High Mount Stop Lamp Assembly Tip: The stop lamp assembly is a Light Emitting Diode (LED) and is serviced as an assembly. Ensure the nine foam gaskets are in place prior to installing the new high mounted stop lamp to the rear compartment lid.
CAUTION
Refer to Fastener Caution .

Scheme 49

Scheme 49: High Mount Stop Lamp Replacement (Wagon)
Scheme 49: High Mount Stop Lamp Replacement (Wagon)
CalloutComponent Name
Preliminary Procedures Open and support the liftgate. Remove the liftgate upper applique. Refer to Liftgate Upper Applique Replacement (Wagon) . Disconnect the electrical connector for the radio antenna cable extension cable assembly.
1High Mount Stop Lamp Nut (Qty: 8) CAUTION: Refer to Fastener Caution . Tighten: 2.5 N.m (22 lb in)
2High Mount Stop Lamp Assembly Procedure Remove the lamp assembly from the alignment pins on the underside of the liftgate upper applique. Remove the rear window washer nozzle from the high mount stop lamp assembly. The high mount stop lamp is a Light Emitted Diode (LED) and is serviced as an assembly.
CAUTION
Refer to Fastener Caution .

Scheme 50

Scheme 50: Cargo Lamp Replacement (Wagon)
Scheme 50: Cargo Lamp Replacement (Wagon)
CalloutComponent Name
1Cargo Lamp Procedure Using a flat bladed tool, release cargo lamp from trim panel. Disconnect the electrical connector.

Scheme 51

Scheme 51: Rear License Plate Lamp Replacement (Sedan, V-Series)
Scheme 51: Rear License Plate Lamp Replacement (Sedan, V-Series)
CalloutComponent Name
Preliminary Procedure: Depress the outside of the rear license plate lamp with a flat-bladed tool and pull the lamp inward to remove the lamp from the rear compartment lid lower molding assembly.
1Rear License Plate Lamp Assembly
2License Plate Lamp Electrical Connector Tip: Rotate the bulb socket a quarter turn counter-clockwise and remove the lamp housing.
3Rear License Plate Lamp Bulb Socket Tip: Pull the bulb straight out of the bulb socket.

Scheme 52

Scheme 52: Rear License Plate Lamp Replacement (Wagon)
Scheme 52: Rear License Plate Lamp Replacement (Wagon)
CalloutComponent Name
Preliminary Procedure: Open and support the liftgate assembly.
1Rear License Plate Lamp Procedure Depress the tab on the left side license plate lamp. Pull the lamp downward from the center liftgate panel opening. Rotate and remove the electrical lamp socket from the lamp. Replace the lamp bulb, as needed.

Scheme 53

Scheme 53: Tail Lamp Replacement (Sedan, V-Series)
Scheme 53: Tail Lamp Replacement (Sedan, V-Series)
CalloutComponent Name
Preliminary Procedures Open the rear compartment lid. Remove the interior rear compartment side trim panel. Refer to Rear Compartment Side Trim Panel Replacement . Disengage the rear compartment weatherstrip from the rear tail lamp being serviced.
1Tail Lamp Assembly Nut (Qty: 3) CAUTION: Refer to Fastener Caution . Tighten: 6 N.m (53 lb in)
2Tail Lamp Assembly Procedure Pull the top of the lamp assembly slightly outward. Pull the lamp rearward in order to disconnect the two outer locator pins from the bodyside outer panel. Lift and slightly swing left, for the left tail lamp, right for the right tail lamp, in order to clear the rear bumper fascia Extreme care should be taken when disconnecting the tail lamp electrical connector from the tail lamp housing. Use only a flat-bladed tool, 3/8" (9.5 mm) wide at the tip and insert the flat-blade between the upper tail lamp housing and electrical connector locking tab. Carefully insert the flat-blade no more than 5/8" (15.8 mm) deep into the tail lamp electrical connector opening. Depress the locking tab, downward on top of the electrical connector and pull to disconnect the electrical connector from the tail lamp assembly. Remove the tail lamp assembly.
CAUTION
Refer to Fastener Caution .

Scheme 54

Scheme 54: Tail Lamp Replacement (Wagon)
Scheme 54: Tail Lamp Replacement (Wagon)
CalloutComponent Name
Preliminary Procedure Open and support the liftgate assembly. Pull the liftgate weatherstrip seal inward away from the tail lamp watershed flange for the lamp being serviced. For the passenger side tail lamp, remove the side access panel door and battery cover. Remove the bodyside rear window garnish molding. Refer to Body Side Window Rear Garnish Molding Replacement (Wagon) . For the driver side tail lamp, remove the bodyside lower trim panel. Refer to Body Side Lower Trim Panel Replacement (Wagon) .
1Quarter Panel Upper Rear Liftgate Opening Molding Screw CAUTION: Refer to Fastener Caution . Tighten: 1.5 N.m (13 lb in)
2Tail Lamp Assembly Nut (Qty: 3) Tighten: 6 N.m (53 lb in)
3Tail Lamp Assembly Procedure Grasp the center of the lamp and pull slightly rearward. Pull the lamp assembly downward slightly in order to release the upper tail lamp hook from the luggage carrier side rail end cap. Extreme care should be taken when disconnecting the tail lamp electrical connector from the tail lamp housing. Use only a flat-bladed tool 3/8" (9.5 mm) wide at the tip and insert the flat-blade between the upper lamp housing and electrical connector locking tab. Carefully insert the flat-blade no more than 5/8" (15.8 mm) deep into the tail lamp electrical connector opening. Depress the locking tab, downward on top of the electrical connector and pull to disconnect the electrical connector from the tail lamp assembly. Remove the tail lamp assembly. Upon installation to the bodyside outer panel, ensure the upper tail lamp assembly hook is positioned into the luggage carrier side rail end cap and the lower tail lamp assembly pin is positioned into the bodyside grommet prior to seating the upper tail lamp retention clip. The integral pin is used for alignment purposes when aligning lamp assembly to the bodyside quarter panel. If the upper retention clip (center view) is pulled from the locator tab, reposition the clip slightly to one side or the other of the witness marks on the tab to ensure positive retention of the clip on the locator tab to the bodyside outer panel of the vehicle.
CAUTION
Refer to Fastener Caution .

Exterior Lamps

The exterior lighting system consist of the following lamps

  1. Adaptive Forward Lighting (AFL)
  2. Automatic Headlamp Leveling - European Only
  3. Headlamps
  4. Daytime running lamps (DRL)
  5. Front fog lamps
  6. Rear fog lamps - European
  7. Park, tail, license and marker lamps
  8. Turn signal lamps
  9. Hazard warning lamps
  10. Repeater lamps - European
  11. Stop lamps
  12. Backup lamps
  13. Position lamps

Low Beam Headlamps (Standard)

The headlamps consist of 2 interchangeable single filament bulbs or 2 high intensity discharge (HID) arc tubes and ballast on each side of the vehicle which provide high and low beams. The lower bulb in the headlamp is the high beam and the upper bulb is the low beam.

The headlamps may be turned ON in 3 different ways

  1. When the headlamp switch is placed in the ON position, for normal operation
  2. When the headlamp switch is placed in the AUTO position, for automatic lamp control (ALC)
  3. When the headlamp switch is placed in the AUTO position, with the windshield wipers ON in daylight conditions, after a 6 second delay

Battery voltage is applied at all times to the coil and switched side of the low beam relay. Ground is applied at all times to the turn signal/multifunction switch. When the turn signal/multifunction switch is placed in the HEAD position, ground is applied from the turn signal/multifunction switch through the headlamps ON signal circuit to the body control module (BCM). The BCM applies ground to the headlamp low beam relay control circuit. This energizes the low beam relay, closing the switched side and applies battery voltage to the LEFT and RIGHT LOW BEAM fuses. Battery voltage is then applied from the fuses, through the low beam voltage supply circuits to the left and right low beam headlamp assemblies illuminating the low beam headlamps.

High Intensity Discharge (HID) Low Beam Headlamps (uplevel)

WARNINGThe high intensity discharge system produces high voltage and current. To reduce the risk of severe shocks and burns: Never open the high intensity discharge system ballast or the arc tube assembly starter. Never probe between the high intensity discharge system ballast output connector and the arc tube assembly.

Battery voltage is applied at all times to the coil and switched side of the low beam relay. Ground is applied at all times to the turn signal/multifunction switch. When the turn signal/multifunction switch is placed in the HEAD position, ground is applied from the turn signal/multifunction switch through the headlamps ON signal circuit to the body control module (BCM). The BCM applies ground to the headlamp low beam relay control circuit. This energizes the low beam relay coil, closing the switch side contacts, and applies battery voltage to the LEFT and RIGHT LOW BEAM fuses. Battery voltage is then applied from the fuses, through the low beam voltage supply circuits to the left and right headlamp ballast located in each headlamp assembly. When battery voltage is applied to the headlamp ballast through the low beam voltage supply circuits, the ballast charge the starter to start the lamp. High intensity discharge (HID) headlamps do not have filaments like traditional bulbs, instead the starter uses a high voltage transformer to convert the input voltage into a higher voltage. This increased voltage is used in order to create an arc between the electrodes in the bulb.

Run Up Of The Lamp

Each ballast requires higher amperage in order to ensure normal startup and run up of the lamp. Run up is the term used to describe the extra power level given to the bulb. The input current during the steady state operation is lower that the start up amperage. After the lamp receives the strike from the starter and the arc is established, the ballast uses its operating voltage in order to provide the run up power needed in order to keep the lamp on. The lamp rapidly increases in intensity from a dim glow to a very high-intensity, bright light called a steady state. Within a few seconds of the arc being established in the bulb, the majority of steady state is complete. 100 percent of the steady state is completed shortly there after. A high watt power level is necessary in order to bring the lamp to a steady state in such a short period of time. The high watt power level allows the lamp to meet the SAE light vs. time specification.

When To Change The HID Bulb

Bulb failure, end of life occurs when the bulb gets old and becomes unstable. The bulb may begin shutting itself off sporadically and unpredictably at first, perhaps only once during a 24-hour period. When the bulb begins shutting itself off occasionally, the ballast will automatically turn the bulb back on again within 0.5 seconds. The ballast will re-strike the bulb so quickly that the bulb may not appear to have shut off. As the bulb ages, the bulb may begin to shut off more frequently, eventually over 30 times per minute. When the bulb begins to shut off more frequently, the ballast receives excessive, repetitive current input. Repetitive and excessive restarts or re-strikes, without time for the ballast to cool down, will permanently damage the ballast. As a safeguard, when repetitive re-strikes are detected, the ballast will not attempt to re-strike the lamp. The ballast then shuts down and the bulb goes out.

The following symptoms are noticeable signs of bulb failure

  1. Flickering light, caused in the early stages of bulb failure
  2. Lights go out, caused when the ballast detects excessive, repetitive bulb re-strike
  3. Color change-The lamp may change to a dim pink glow.

Input power to the ballast must be terminated in order to reset the ballast's fault circuitry. In order to terminate the input power to the ballast, turn the lights off and back on again. Turning the lights off and back on again resets all of the fault circuitry within the ballast until the next occurrence of excessive, repetitive bulb re-strikes. When excessive, repetitive bulb re-strikes occur, replace the starter/arc tube assembly. The ballast will begin the start-up process when the starter/arc tube assembly is replaced. Repeatedly resetting the input power can overheat the internal components and cause permanent damage to the ballast. Allow a few minutes of cool-down time in between reset attempts.

Bulb failures are often sporadic at first, and difficult to repeat. Technicians can identify bulb failure by observing if the problem gets progressively worse over the next 100 hours of operation.

Light Color

White light has a different color rating than regular headlamps. The range of white light that is acceptable is broad when compared to halogens. Therefore, some variation in headlight coloring between the right and left headlamp will be normal. One high intensity discharge (HID) at the end of the normal range may appear considerably different in color from one at the other end of the range. Difference in color is normal. Replace the arc tube only if the arc tube is determined to be at the bulb failure stage.

Adaptive Forward Lighting (AFL)

The AFL consist of the following components

  1. Headlamp control module
  2. Headlamp actuator - left
  3. Headlamp actuator - right

Battery positive voltage is applied to the headlamp control module at all times and when the ignition switch is in the RUN and CRANK positions. The headlamp control module has an operational voltage range of about 10.5-16 volts and is only fully functional when the ignition switch is in the RUN position. The voltage input from the ignition switch wakes the headlamp control module microprocessor. The headlamp control module receives serial data messages from the engine control module (ECM), transmission control module (TCM), electronic brake control module (EBCM), and body control module (BCM) with regards to power mode, speed, steering angle, transmission gear selection, and headlamp switch status. The headlamp control module calculates the headlamp angle and sends commands to the left and right headlamp actuators. The headlamp actuators drive the headlamps to the position commanded by the headlamp control module. The headlamp control module monitors the headlamp actuator motor control circuits for proper circuit continuity and for shorts to ground or voltage. If a malfunction is detected, a DTC will be stored in memory and the driver will be notified with a message displayed over the driver information center (DIC) located on the instrument panel cluster (IPC).

The headlamp control module controls the left headlamp movement by 15 degrees to the left and 5 degrees to the right, and the right headlamp movement by 5 degrees to the left and 15 degrees to the right. The direction the headlamps move is controlled by the steering wheel angle and is limited by steering angles of approximately +/- 90 degrees. The AFL will not operate with the transmission in reverse or at vehicle speeds less than 2 mph. Movement of the headlamps is restricted at low vehicle speeds and full movement of the lamps is not allowed until vehicle speed is greater than approximately 30 mph. The following conditions must be met before the AFL will operate

  1. Headlamp switch in the AUTO position and high or low beam headlamps must be active
  2. Steering angle position must be received from the EBCM with the steering signal validity bit set
  3. Vehicle speed must be received from the ECM with the steering signal validity bit set
  4. Transmission gear position must be received from the TCM with the transmission gear position validity bit set

Automatic Lamp Control/Twilight Sentinel

Place the turn signal/multifunction switch in the AUTO position for automatic lamp control. During automatic lamp control the headlamps will be off during daylight conditions but will turn on when the ambient light sensor detects low outside light level. The ambient light sensor is a light sensitive transistor that varies the voltage signal to the HVAC control module. The HVAC control module sends a signal to the body control module (BCM) via serial data commanding the BCM to apply ground to the headlamp low beam relay control circuit. This energizes the low beam relay, closing the switched side and applies battery voltage to the LEFT and RIGHT LOW BEAM fuses. Battery voltage is applied from the low beam fuses, through the low beam voltage supply circuits to low headlamp assemblies.

Flash to Pass (FTP)

When the low beam headlamps are on and the turn signal/multifunction switch is momentarily placed in the flash to pass (FTP) position, ground is applied to the turn signal/multifunction switch. The turn signal/multifunction switch applies ground to the body control module (BCM) through the FTP switch signal circuit. The BCM then applies ground to the high beam relay control circuit. This energizes the high beam relay, closing the switch side contacts of the high beam relay, applying battery voltage to the LEFT and RIGHT HIGH BEAM fuses. Battery voltage is applied from the High Beam fuses through the high beam voltage supply circuit to the high beam headlamp assemblies. This causes the high beam headlamps to illuminate at full brightness momentarily or until the flash to pass switch is released.

Automatic Headlamp Leveling - European Only

The Automatic Headlamp Leveling Systems consist of the following components

  1. Ballast module - left
  2. Ballast module - right
  3. Headlamp leveling actuator - left
  4. Headlamp leveling actuator - right
  5. Headlamp control module
  6. Front headlamp leveling sensor - base
  7. Rear headlamp leveling sensor - base
  8. Left front strut position sensor - V-series
  9. Left rear strut position sensor - V-series
  10. Right front strut position sensor - V-series
  11. Right rear strut position sensor - V-series

Base

The automatic headlamp leveling system automatically maintains the vertical alignment of the headlamps when the vehicle load and driving conditions change. Each headlamp assembly contains a headlamp leveling motor that is controlled by the headlamp control module. The front and rear suspension position sensors provide the headlamp control module with suspension position information. Each sensor receives a 5-volt reference, signal, and low reference circuits from the headlamp control module. The sensors are connected to the control arms of the front and rear suspension. As the vehicle travels, the suspension compresses and rebounds moving the suspension position sensor arms. This causes the signal output of the sensor to change. The headlamp control module compares the information from both suspension position sensors and adjusts the headlamp leveling as needed. The headlamp control module is wired to each headlamp leveling motor with 4 directional motor control circuits.

V-Series

The automatic headlamp leveling system automatically maintains the vertical alignment of the headlamps when the vehicle load and driving conditions change. Each headlamp assembly contains a headlamp leveling motor that is controlled by the headlamp control module. The front and rear suspension position sensors provide the electronic suspension control (ESC) module with suspension position information. Each sensor receives a 5-volt reference, signal, and low reference circuits from the ESC. The sensors are connected to the control arms of the front and rear suspension. As the vehicle travels, the suspension compresses and rebounds moving the suspension position sensor arms. This causes the signal output of the sensor to change. The ESC sends the suspension position sensor values to the headlamp control module via serial data. The headlamp control module compares the information from both suspension position sensors and adjusts the headlamp leveling as needed. The headlamp control module is wired to each headlamp leveling motor with 4 directional motor control circuits. For more detailed information regarding ESC, refer to Electronic Suspension Control Description and Operation .

Daytime Running Lamps (DRL) without HID

The daytime running lamps (DRL) will illuminate the right and left low beam headlamps continuously. The DRLs will operate when the following conditions are met

  1. The ignition is in the RUN or CRANK position
  2. The shift lever is out of the PARK position for vehicles equipped with automatic transmissions or the parking brake is released for vehicles with manual transmissions.
  3. The high and low beam headlamps are OFF.

The ambient light sensor is used to monitor outside lighting conditions. The ambient light sensor provides a voltage signal that will vary between 0.2 and 4.9 volts depending on outside lighting conditions. The HVAC control module provides a low reference ground and 5-volt reference to the ambient light sensor. The body control module (BCM) monitors the ambient light sensor signal circuit to determine if outside lighting conditions are correct for either daytime running lights (DRL) or automatic lamp control (ALC) when the headlamp switch is in the AUTO position. In daylight conditions the BCM will command the low beam headlamps ON. Any function or condition that turns on the headlamps will cancel DRL operation.

Daytime Running Lamps (DRL) with HID

The daytime running lamps (DRL) will illuminate continuously when the following conditions are met

  1. The ignition is in the RUN or CRANK position
  2. The shift lever is out of the PARK position for vehicles equipped with automatic transmissions or the parking brake is released for vehicles with manual transmissions.
  3. The high and low beam headlamps are OFF.

The ambient light sensor is used to monitor outside lighting conditions. The ambient light sensor provides a voltage signal that will vary between 0.2 and 4.9 volts depending on outside lighting conditions. The HVAC control module provides a low reference ground and 5-volt reference signals to the ambient light sensor. The body control module (BCM) monitors the ambient light sensor signal circuit to determine if outside lighting conditions are correct for either daytime running lights (DRL) or automatic lamp control (ALC) when the headlamp switch is in the AUTO position. In daylight conditions, the BCM will command the DRLs ON by applying ground to the left and right DRL relays via separate left and right DRL relay control circuits. When the BCM applies ground to the relay control circuits, the left and right DRL relay coils energize causing both relay switch contacts to close. With the left and right DRL relay switch contacts closed, battery voltage flows through the left and right DRL fuses to the left and right DRL lamps. Any function or condition that turns on the headlamps will cancel DRL operation.

Front Fog Lamps

The front fog lamp relay coil and switch terminals are supplied with battery voltage at all times. Ground is applied at all times to the front fog lamp switch inside of the turn signal/multifunction switch. When the front fog lamp switch is placed in the ON position, ground is applied through the front fog lamp switch signal circuit to the body control module (BCM). The body control module (BCM) energizes the front fog lamp relay coil by applying ground to the front fog lamp relay control circuit. When the front fog lamp relay is energized, the relay switch contacts close and battery voltage is applied through the FRONT FOG LAMP fuse to the front fog lamp supply voltage circuit which illuminates the front fog lamps.

The BCM will send a serial data message to the instrument panel cluster (IPC) to enable the front fog lamp indicator. The front fog lamps will deactivate when either the flash-to-pass or the high beam headlamps are turned ON.

Rear Fog Lamps

The rear fog lamp relay coil and switch terminals are supplied with battery voltage at all times. Ground is applied at all times to the rear fog lamp switch inside of the turn signal/multifunction switch. When the rear fog lamp switch is placed in the ON position, ground is applied through the rear fog lamp switch signal circuit to the body control module (BCM). Battery voltage is applied at all times from the REAR FOG LAMP fuse to the REAR FOG LAMP relay. The BCM applies ground through the rear fog lamp relay control circuit to the coil side of the REAR FOG LAMP relay causing the relay coil to energize. When the relay is energized, the switch contacts close and battery voltage is applied from the REAR FOG LAMP fuse through the relay, to the rear fog lamps.

The BCM will send a serial data message to the instrument panel cluster (IPC) to enable the rear fog lamp indicator.

The rear tail, stop, and turn signal functions are performed by light emitting diodes (LED) in the tail lamp assemblies. The tail lamp assemblies wrap around the corner of the vehicle and serve as the rear side marker. The lower portion of each lamp contains reflectors to alert approaching vehicles for nighttime driving safety. Battery positive voltage is applied at all times to both the coil and switch sides of the LT/POS/LP relay located in the rear fuse block. The turn signal/multifunction switch is suppled with ground at all times. When the headlamp switch is placed in either the HEAD or PARK position, ground is applied to the park lamp signal circuit to the body control module (BCM). The BCM responds by applying ground to the park lamp relay control circuit. This energizes the park lamp relay coil causing the relay switch contacts to close allowing battery voltage to flow through the LT/POS/LP and RT/POS/LP fuses to all of the park, tail, license, and marker lamps.

The rear tail, stop, and turn signal functions are performed by light emitting diodes (LED) in the tail lamp assemblies. The tail lamp assemblies wrap around the corner of the vehicle and serve as the rear side marker. The lower portion of each lamp contains reflectors to alert approaching vehicles for nighttime driving safety. Battery positive voltage is applied at all times to both the coil and switch sides of the LT/POS/LP and RT/POS/LP relays located in the rear fuse block. The turn signal/multifunction switch is suppled with ground at all times. When the headlamp switch is placed in either the HEAD or PARK position, ground is applied to the park lamp signal circuit to the body control module (BCM). The BCM responds by applying ground to the left and right park lamp relay control circuits. This energizes the left and right park lamp relay coils causing the relay switch contacts to close allowing battery voltage to flow through the LT/POS/LP and RT/POS/LP fuses to all of the park, tail, license, and marker lamps.

Turn Signal Lamps

Ground is applied at all times to the turn signal/multifunction switch. The turn signal lamps may only be activated with the ignition switch in the ON or START position. When the turn signal/multifunction switch is placed in either the TURN RIGHT or TURN LEFT position, ground is applied to the body control module (BCM) through either the right turn or left turn signal switch circuit. Battery voltage is applied at all times to the BCM. The BCM then applies a pulsating voltage to the front and rear turn signal lamps.

Repeater Lamps

The repeater lamps are on export vehicles only. Each lamp is located in the front fender. The repeater lamps are used as additional turn signal lamps, and operate as described in the Turn Signal/Hazard Flasher Lamps description.

Hazard Flasher Lamps

The hazard flashers may be activated in any power mode. The hazard switch is located on the radio/HVAC control panel. The hazard switch signal circuit is momentarily grounded when the hazard switch is pressed. The BCM supplies battery voltage to all four turn signal lamps in an ON and OFF duty cycle. When the hazard switch is activated, the BCM sends a serial data message to the instrument panel cluster (IPC) requesting both turn signal indicators to be cycled ON and OFF.

The brake pedal position sensor is used to sense the action of the driver application of the brake pedal. The brake pedal position sensor provides an analog voltage signal that will increase as the brake pedal is applied. The body control module (BCM) provides a low reference signal and a 5-volt reference voltage to the brake pedal position sensor. When the variable signal reaches a voltage threshold indicating the brakes have been applied, the BCM will apply battery voltage to the right and left stop lamp control circuits, transmission control module (TCM), engine control module (ECM), and center high mounted stop lamp (CHMSL) control circuit. The stop lamps on this vehicle will not illuminate unless the ignition is in the accessory, run, or crank positions. When the ignition is in the OFF position the stop lamps will not illuminate when the brake pedal is applied.

The brake pedal position sensor is used to sense the action of the driver application of the brake pedal. The brake pedal position sensor provides an analog voltage signal that will increase as the brake pedal is applied. The body control module (BCM) provides a low reference signal and a 5-volt reference voltage to the brake pedal position sensor. When the variable signal reaches a voltage threshold indicating the brakes have been applied, the BCM will apply battery voltage to stop lamp relay coil side control circuit, transmission control module (TCM), engine control module (ECM), and center high mounted stop lamp (CHMSL). When the stop lamp relay receives battery voltage from the BCM, the relay coil is energized and the stop lamp relay switch contacts close applying battery voltage from the STOP LAMPS fuse to illuminate the left and right stop lamps and trailer stop lamps. The stop lamps on this vehicle will not illuminate unless the ignition is in the accessory, run, or crank positions. When the ignition is in the OFF position the stop lamps will not illuminate when the brake pedal is applied.

Backup Lamps

When the transmission is placed in the REVERSE position, the transmission control module (TCM) sends a serial data message to the body control module (BCM). The message indicates that the gear selector is in the REVERSE position. The BCM applies battery voltage to the backup lamps and inside rearview mirror. The backup lamps are permanently grounded. Once the driver moves the gear selector out of the REVERSE position, a message is sent by the TCM via serial data requesting the BCM to remove battery voltage from the backup lamp control circuit. The engine may need to be running for the backup lamps to function.

Battery Run Down Protection/Inadvertent Power

To provide battery run down protection, the exterior lamps will be deactivated automatically under certain conditions. The body control module (BCM) monitors the state of the headlamp switch. If the park or headlamp switch is ON when the ignition switch is placed in either the CRANK or RUN position and then placed in the OFF position, the BCM initiates a 10 minute timer. At the end of the 10 minutes, the BCM will turn off the control power output to the park and headlamp relay coils, deactivating the exterior lamps. This feature will be cancelled if any power mode other than OFF becomes active. The BCM will disable battery run down protection if any of the following conditions exist. The park or headlamp switch is placed in the ON to OFF position, and back to the ON position during battery run down protection. The BCM determined that the park or headlamp switch was not active when the ignition was turned OFF.

Interior Lamps

The interior lighting consist of two groups. This first group includes lamps that may not be dimmed.

  1. Courtesy/ Illuminated Entry Lamps
  2. The Inside Rearview Mirror Lamps
  3. The Vanity Mirror Lamps
  4. The IP Compartment Lamps

Courtesy Lamps

The courtesy lamps include the instrument panel courtesy lamps, the exterior courtesy lamps, and the rear view mirror lamps. Turn the courtesy lamps ON manually by placing the interior lamp switch in the DOME position, by opening a door or opening the trunk. After all the doors have been closed the courtesy lamps will remain illuminated approximately 15 seconds after the last door closes. The courtesy lamps will also turn ON prior to any door being opened, and remain illuminated approximately 30 seconds after the driver removes the ignition key.

The BCM 3 fuse supplies battery positive voltage to the BCM. The BCM then applies battery positive voltage to the courtesy lamps through the inadvertent power supply circuit. When any door or if the trunk is opened, the jam switch contacts close and the BCM receives a door-open or trunk open input. If the BCM receives a door lock or unlock input or an trunk open input, the BCM will activate the inadvertent power circuit, providing battery positive voltage to all of the IP courtesy lamps and the rearview mirror lamps. The BCM also provides a class 2 message signal to the driver door module and passenger door module to apply battery positive voltage to the exterior courtesy lamps. You may use some of the courtesy lamps as reading lamps by placing the lamp switch in the ON position.

The courtesy lamps will normally turn OFF using the theater dimming feature. The BCM provides a pulse width modulated ground to the courtesy/reading and inside rear view mirror lamps for the theater dimming feature. The BCM turns OFF the courtesy lamps if a door lock command is received after all of the doors are closed, or if the ignition switch is turned to either the ON or RUN position.

The courtesy lamps will also turn on after an air bag deployment for approximately 15 seconds.

Keyless Entry Interior Illumination

When the driver uses the door key in order to unlock the doors, BCM receives a door-unlock signal. The BCM must have inputs that indicate that the ignition switch is OFF, the courtesy lamp switch is OFF and all the doors are closed. The BCM will then activate the interior lamps. The courtesy lamps will remain ON for 15 seconds after the door is closed. The BCM will turn off the courtesy lamps through the theater dimming feature. If the door locks are activated to the LOCK position, or if the ignition switch is turned to either the RUN or CRANK position, the courtesy lamps will turn OFF immediately.

When the driver uses the remote function actuator transmitter to unlock the doors or the trunk or to press the panic button, the BCM will keep the courtesy lamps ON for 30 seconds. If the door locks are activated to the UNLOCK or LOCK position, or if the ignition switch is turned to either the RUN or CRANK position, the courtesy lamps turn OFF immediately. The BCM keeps the courtesy lamps on for 40 seconds after an alarm event is completed.

Vanity Lamps

The BCM 2 fuse supplies battery positive voltage to the BCM. The BCM then applies battery positive voltage to the vanity lamps through the inadvertent power supply circuit. When the vanity mirror cover on the sunshade is opened, its switch closes providing a ground circuit, and the vanity lamp illuminates.

IP Compartment Lamp

The BCM 2 fuse supplies battery positive voltage to the BCM. The BCM then applies battery positive voltage to the IP compartment lamp through the inadvertent power supply circuit. When the IP compartment is opened, its switch closes providing a ground circuit, and the IP compartment lamp illuminates.

Interior Lamps Dimming

The second group includes lamps which may be dimmed. This group may use a combination of vacuum fluorescent (VF) illumination, incandescent lamps and pulse width modulation (PWM) illumination.

  1. The Hazard Switch
  2. The Door Switches and the Window Switches
  3. The Steering Wheel Controls
  4. The HVAC Control Head Assembly
  5. The Ignition Switch
  6. The Radio
  7. The Rear Compartment/Fuel Door Release Switch
  8. The Traction/Suspension Control Switch
  9. The Power Seat Switch
  10. The transmission range selector
  11. The Power Sun Roof Switch
  12. The Fog Lamp Switch
  13. The Front and Rear Fog Lamp Switch (Export)

When the ignition switch is turned to the ON position, the vacuum fluorescent (VF) displays, for radio and HVAC control assembly, the incandescent lamps and the PWM lamps turn ON at maximum brightness. When the park lamps are ON and the ambient light sensor indicates low light conditions, all back lighting turn ON at the dimming level indicated by the IP dimmer switch. At the same time all VF displays dim in order to match the indicated dimming level. When the headlamp switch is placed in the PARK position, the BCM energizes the park lamp relay coil control circuit and dims the interior lamps to the dimming level indicated by the IP dimmer switch. When the driver selects a dimming setting by moving the IP dimming switch potentiometer, all back lighting lamps are provided with a specific voltage. When the IP dimmer switch is moved from MIN to MAX, all VF displays and all back lighting respond from minimum intensity to maximum brightness in response to the IP dimmer switch. The I/P dimmer switch is provided with a B+ voltage reference circuit from the BCM. The BCM receives B+ from the BCM 1 fuse.

The driver may select parade mode by manually turning on the park lamps during daylight conditions.

Driver Controls and Modules

Driver controls include the following components

  1. The Emergency Flasher Switch
  2. The Fog Lamp Switch
  3. The Headlamp Dimmer Switch
  4. The Headlamp Switch
  5. The Interior Lamp Switch
  6. The IP Dimmer Switch
  7. The Stop Lamp Switch
  8. The Turn Signal Switch

Three modules process the inputs and the controls. The ambient light sensor supplies the BCM with a signal for daytime conditions or for low light conditions.

  1. The Ambient Light Sensor
  2. The Body Control Module (BCM)
  3. The Instrument Panel Cluster (IPC)

Battery Rundown Protection / Inadvertent Power

The BCM controls the lighting system through circuits that enable both the exterior lamp functions of the park lamps, the head lamps, the fog lamps, and the interior lamps. The BCM opens these enabling circuits 20 minutes after the ignition switch is turned OFF with no lamp switch activity. If the ignition switch is turned to any position other than OFF, or if a lamp switch is activated during this 10 minute period, the timer resets for another 20 minutes.

See also:
• Diagnostic System Check - Vehicle
• Strategy Based Diagnosis
• Diagnostic Procedure Instructions
• Component Connector End Views
• Circuit Testing
• Connector Repairs
• Testing for Intermittent Conditions and Poor Connections
• Wiring Repairs
• Control Module References
• Diagnostic Repair Verification
• Relay Replacement (Attached to Wire Harness)
• Inside Rearview Mirror Replacement
• Turn Signal Multifunction Switch Replacement
• Electronic Suspension Control Schematics
• Checking Aftermarket Accessories
• Door Lock/Indicator Schematics
• Sunshade Replacement
• Radio Control Assembly Replacement (with Navigation Display)
• Driver Seat Schematics
• Rear Side Door Window Switch Replacement
• Driver Information Display Switch Replacement
• Steering Wheel Control Switch Assembly Replacement
• Trailer Connector/Provision Schematics
• Driver Knee Bolster Replacement (Left Hand Drive)
• Fastener Caution
• Instrument Panel Outer Air Outlet Deflector Replacement - Left Side
• Halogen Bulb Warning
• Front Bumper Fascia Replacement
• Lifting and Jacking the Vehicle
• Tire and Wheel Removal and Installation
• Wheelhouse Extension Replacement
• Liftgate Upper Applique Replacement (Wagon)
• DTC B1010
• Headlamp Assembly or Headlamp Bulb and/or Cornering, Sidemarker, Park, Turn Signal Bulb Replacement (TT8)
• Brake Pedal Position Sensor Calibration
• Brake Pedal Position Sensor Replacement
• Headlamp Ballast Replacement (European)