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Contents Wiring diagrams Section: Exterior Lights All sections

Lighting System Cadillac ELR I

Exterior Lights 43 illustrations ~39959 words

Fastener Tightening Specifications

ApplicationSpecification
MetricEnglish
Back Up Lamp to Rear Bumper Fascia Screw2.5 N.m22 lb in
Brake Pedal Position Sensor Bolt9 N.m80 lb in
Daytime Running Lamp Screw2.5 N.m22 lb in
Headlamp Screw2.5 N.m22 lb in
High Mount Stop Lamp Nut4.7 N.m42 lb in
Tail Lamp Nut4.7 N.m42 lb in

Fastener Tightening Specifications

Scheme 1

Scheme 1: Daytime Running Lamps and Low Beams
Scheme 1: Daytime Running Lamps and Low Beams

Scheme 2

Scheme 2: High Beams
Scheme 2: High Beams

Scheme 3

Scheme 3: Park, Tail and License Lamps
Scheme 3: Park, Tail and License Lamps

Scheme 4

Scheme 4: Front Turn Signals and Controls
Scheme 4: Front Turn Signals and Controls

Scheme 5

Scheme 5: Rear Turn Signals, Stop Lamps, and Backup Lamp
Scheme 5: Rear Turn Signals, Stop Lamps, and Backup Lamp

Scheme 6

Scheme 6: Controls and Courtesy Lamps
Scheme 6: Controls and Courtesy Lamps

Scheme 7

Scheme 7: Instrument Panel Compartment, Floor Console Compartment and Overhead Courtesy Lamps
Scheme 7: Instrument Panel Compartment, Floor Console Compartment and Overhead Courtesy Lamps

Scheme 8

Scheme 8: Accent Lamps - Instrument Panel, Console and Overhead
Scheme 8: Accent Lamps - Instrument Panel, Console and Overhead

Scheme 9

Scheme 9: Accent Lamps - Doors
Scheme 9: Accent Lamps - Doors

Scheme 10

Scheme 10: Controls and Instrument Panel Lamps
Scheme 10: Controls and Instrument Panel Lamps

Scheme 11

Scheme 11: Door Lamps
Scheme 11: Door Lamps

Scheme 12

Scheme 12: Floor Console and Overhead Lamps
Scheme 12: Floor Console and Overhead Lamps

Diagnostic Code Index

DTCDescription
DTC B096FDTC B096F 01 Power Mode Switch Assembly Backlight Circuit Short to Battery DTC B096F 02 Power Mode Switch Assembly Backlight Circuit Short to Ground DTC B096F 04 Power Mode Switch Assembly Backlight Circuit Open
DTC B1395DTC B1395 03 Control Module Voltage Reference Output Circuit Low Voltage DTC B1395 07 Control Module Voltage Reference Output Circuit High Voltage
DTC B1480DTC B1480 02 Battery Rundown Protection Circuit Short to Ground
DTC B2540DTC B2540 02 Rear Fog Lamps Control Circuit Short to Ground DTC B2540 04 Rear Fog Lamps Control Circuit Open
DTC B2545DTC B2545 01 Backup Lamps Circuit Short to Battery DTC B2545 02 Backup Lamps Circuit Short to Ground DTC B2545 04 Backup Lamps Circuit Open
DTC B2570DTC B2570 02 Trunk Lamp Control Circuit Short to Ground
DTC B257ADTC B257A 00 Headlamp Switch Input Signals Correlation Malfunction
DTC B2580DTC B2580 01 Headlamp High Beam Control Circuit Short to Battery DTC B2580 02 Headlamp High Beam Control Circuit Short to Ground DTC B2580 04 Headlamp High Beam Control Circuit Open
DTC B2585 or B3867DTC B2585 01 Left Park Lamps Control Circuit Short to Battery DTC B2585 02 Left Park Lamps Control Circuit Short to Ground DTC B2585 04 Left Park Lamps Control Circuit Open DTC B3867 01 Right Park Lamp Control Circuit Short to Battery DTC B3867 02 Right Park Lamp Control Circuit Short to Ground DTC B3867 04 Right Park Lamp Control Circuit Open
DTC B2600 or B2605DTC B2600 02 Left Daytime Running Lamps Control Circuit Short to Ground DTC B2605 02 Right Daytime Running Lamps Control Circuit Short to Ground
DTC B2610DTC B2610 01 Passenger Compartment Dimming 1 Circuit Short to Battery DTC B2610 02 Passenger Compartment Dimming 1 Circuit Short to Ground DTC B2610 04 Passenger Compartment Dimming 1 Circuit Open
DTC B2615DTC B2615 02 Passenger Compartment Dimming 2 Circuit Short to Ground
DTC B2625DTC B2625 02 Display Dimming Pulse Width Modulation Output Circuit Short to Ground
DTC B2645DTC B2645 03 Ambient Light Sensor Circuit Low Voltage DTC B2645 07 Ambient Light Sensor Circuit High Voltage
DTC B3588DTC B3588 00 Rear Fog Lamp Switch Circuit Malfunction
DTC B3596DTC B3596 00 Hazard Lamps Request Circuit Malfunction
DTC B3600DTC B3600 03 Passenger Compartment Dimming Request Signal Circuit Low Voltage DTC B3600 07 Passenger Compartment Dimming Request Signal Circuit High Voltage
DTC B3650DTC B3650 08 High Beam Request Signal Circuit Performance - Signal Invalid
DTC B3806DTC B3806 00 High Beam and Headlamp Flash Select Circuit Malfunction
DTC B3881 or B3882DTC B3881 01 Left Tail Lamp Circuit Short to Battery DTC B3881 02 Left Tail Lamp Circuit Short to Ground DTC B3881 04 Left Tail Lamp Circuit Open DTC B3882 01 Right Tail Lamp Circuit Short to Battery DTC B3882 02 Right Tail Lamp Circuit Short to Ground DTC B3882 04 Right Tail Lamp Circuit Open
DTC B3883DTC B3883 01 License Plate Lamp Circuit Short to Battery DTC B3883 02 License Plate Lamp Circuit Short to Ground DTC B3883 04 License Plate Lamp Circuit Open
DTC B3884DTC B3884 01 Center High Mounted Brake Lamp Circuit Short to Battery DTC B3884 02 Center High Mounted Brake Lamp Circuit Short to Ground DTC B3884 04 Center High Mounted Brake Lamp Circuit Open
DTC B3948 or B3949DTC B3948 01 Left Front Turn Signal Circuit Short to Battery DTC B3948 02 Left Front Turn Signal Circuit Short to Ground DTC B3948 04 Left Front Turn Signal Circuit Open DTC B3949 01 Right Front Turn Signal Circuit Short to Battery DTC B3949 02 Right Front Turn Signal Circuit Short to Ground DTC B3949 04 Right Front Turn Signal Circuit Open
DTC B3950 or B3951DTC B3950 01 Left Rear Turn Signal Circuit Short to Battery DTC B3950 02 Left Rear Turn Signal Circuit Short to Ground DTC B3950 04 Left Rear Turn Signal Circuit Open DTC B3951 01 Right Rear Turn Signal Circuit Short to Battery DTC B3951 02 Right Rear Turn Signal Circuit Short to Ground DTC B3951 04 Right Rear Turn Signal Circuit Open
DTC C0277 or C0890DTC C0277 06 Brake Pedal Position Sensor Circuit Low Voltage/Open DTC C0277 07 Brake Pedal Position Sensor Circuit High Voltage DTC C0277 09 Brake Pedal Position Sensor Circuit Too Fast Transitions DTC C0277 4B Brake Pedal Position Sensor Circuit Calibration Not Learned DTC C0890 03 Control Module Voltage Reference Output 3 Circuit Low Voltage DTC C0890 07 Control Module Voltage Reference Output 3 Circuit High Voltage
DTC C0297DTC C0297 02 Brake Applied Output Circuit Short to Ground

DIAGNOSTIC CODE INDEX

Diagnostic Instructions

  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/elr/i-2013-2015/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/elr/i-2013-2015/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/elr/i-2013-2015/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
Vehicle ON/OFF Switch LED Backlighting ControlB096F 02B096F 04B096F 01
Vehicle ON/OFF Switch Ground1
1. Interior Backlighting Malfunction

Circuit/System Description

The instrument panel dimmer switch is used to increase and decrease the brightness of the interior backlighting components. The instrument panel dimmer switch provides a voltage signal to the body control module (BCM) that will increase as the brightness of the lights are increased and decrease as the brightness of the lights are decreased. The BCM provides a low reference, signal, and B+ circuits to the instrument panel dimmer switch. When the instrument panel dimmer switch is placed in the desired position, the dimmed voltage setting is applied from the instrument panel dimmer switch through the instrument panel dimmer switch signal circuit to the BCM. The BCM interprets the signal and applies a pulse width modulated (PWM) voltage through the LED dimming control circuits illuminating the interior backlighting to the requested level of brightness.

Conditions for Running the DTC

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

Conditions for Setting the DTC

DTC B096F 01

The BCM detects a short to voltage in the vehicle ON/OFF switch LED backlighting control circuit.

DTC B096F 02

The BCM detects a short to ground in the vehicle ON/OFF switch LED backlighting control circuit.

DTC B096F 04

The BCM detects an open/high resistance in the vehicle ON/OFF switch LED backlighting control circuit.

Actions Taken When the DTC Sets

The vehicle ON/OFF switch LED backlighting will not illuminate.

Conditions for Clearing the DTC

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

Reference Information

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/elr/i-2013-2015/remont/body-electrical/#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. Vehicle OFF, scan tool disconnected, all doors closed, all accessories OFF, disconnect the harness connector at the S83 vehicle ON/OFF switch. It may take up to 2 minutes for all vehicle systems to power down.
  2. Test for less than 5 ohms between the ground circuit terminal 4 and ground. If 5 ohms or greater Vehicle OFF. Test for less than 2 ohms in the ground circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, repair the open/high resistance in the ground connection. If less than 5 ohms
  3. Connect a test lamp between the control circuit terminal 8 and ground, vehicle in Service Mode, park lamps ON.
  4. Verify the test lamp intensity changes from low to high as the instrument panel dimmer switch is activated from low to high. If the test lamp is always OFF Vehicle OFF, disconnect the X7 harness connector at the K9 body control module. Test for infinite resistance between the control circuit and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance Test for less than 2 ohms in the control circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K9 body control module. If the test lamp is always ON full intensity Vehicle OFF, disconnect the X7 harness connector at the K9 body control module, vehicle in Service Mode. Test for less than 1 V between the control circuit terminal and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V, replace the K9 body control module. If the test lamp dims from LOW to HIGH
  5. Test or replace the S83 vehicle ON/OFF switch.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.

  1. «Ignition and Start Switch Replacement»(/cadillac/elr/i-2013-2015/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-repair-instructions)
  2. «Control Module References»(/cadillac/elr/i-2013-2015/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM replacement, programming, and setup
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/elr/i-2013-2015/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/elr/i-2013-2015/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/elr/i-2013-2015/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
F10DL (BCM/EXT LIGHTS) FuseC0890 03, B101E 43, B1395 03, B1517 07, U0121 00, U0128 00, U0422 71C0890 03, B101E 43, B1395 03, B1517 07, U0121 00, U0128 00, U0422 71
Instrument Panel Dimmer Switch B+B1395 03, B3600 03B3600 031
Instrument Panel Dimmer Switch SignalB3600 03B3600 03B3600 07, 1
Instrument Panel Dimmer Switch Low Reference111
Driver Information Center Switch Ground1
1. Interior Backlighting Malfunction

The instrument panel dimmer switch is used to increase and decrease the brightness of the interior backlighting components. The instrument panel dimmer switch provides a voltage signal to the body control module (BCM) that will increase as the brightness of the lights are increased and decrease as the brightness of the lights are decreased. The BCM provides B+, low reference, and signal circuits to the instrument panel dimmer switch. When the instrument panel dimmer switch is placed in the desired position, the dimmed voltage setting is applied from the instrument panel dimmer switch through the instrument panel dimmer switch signal circuit to the BCM. The BCM interprets the signal and applies a pulse width modulated (PWM) voltage through the LED dimming control circuits illuminating the interior backlighting to the requested level of brightness.

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

DTC B1395 03

  1. The BCM detects a short to ground in the instrument panel dimmer switch B+ reference circuit.
  2. The BCM detects a short to ground or an open/high resistance in the F10DL fuse B+ circuit.

DTC B1395 07

The BCM detects a short to voltage in the instrument panel dimmer switch B+ reference circuit.

The interior backlighting defaults to FULL bright.

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

Schematic Reference

  1. «Interior Lights Dimming Schematics»(/cadillac/elr/i-2013-2015/remont/exterior-lights/#lighting-system)
  2. «Body Control System Schematics»(/cadillac/elr/i-2013-2015/remont/communication-devices/#data-communication-system-schematic-wiring-diagrams)

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Vehicle OFF, disconnect the harness connector at the S16 driver information center switch, vehicle in Service Mode.
  2. Verify a test lamp illuminates between the low reference circuit terminal 12 and B+. If the test lamp does not illuminate Vehicle OFF, disconnect the X1 harness connector at the K9 body control module, vehicle in Service Mode. Test for less than 1 V between the low reference circuit terminal 12 and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V Test for less than 2 ohms in the low reference circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K9 body control module. If the test lamp illuminates
  3. Test for B+ between the B+ circuit terminal 11 and ground. If less than B+ Vehicle OFF, disconnect the X1 harness connector at the K9 body control module. Test for infinite resistance between the B+ reference circuit and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance Test for less than 2 ohms in the B+ reference circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K9 body control module. If B+
  4. Verify a test lamp does not illuminate between the B+ circuit terminal 11 and ground. If the test lamp illuminates Vehicle OFF, disconnect the X1 harness connector at the K9 body control module, vehicle in Service Mode. Test for less than 1 V between the B+ circuit terminal 11 and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V, replace the K9 body control module. If the test lamp does not illuminate
  5. Verify the scan tool LED Backlight Dimming Command parameter is greater than 40%. If 40% or less Vehicle OFF, disconnect the X2 harness connector at the K9 body control module, vehicle in Service Mode. Test for less than 1 V between the signal circuit terminal 10 and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V, replace the K9 body control module. If greater than 40%
  6. Install a 3 A fused jumper wire between the signal circuit terminal 10 and the B+ circuit terminal 11.
  7. Verify the scan tool LED Backlight Dimming Command parameter is less than 30%. If 30% or greater Vehicle OFF, disconnect the X2 harness connector at the K9 body control module. Test for infinite resistance between the signal circuit and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance Test for less than 2 ohms in the signal circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K9 body control module. If less than 30%
  8. Test or replace the S16 driver information center switch.

Perform the Diagnostic Repair Verification after completing the repair.

Control Module References for BCM replacement, programming, and setup

  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/elr/i-2013-2015/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/elr/i-2013-2015/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/elr/i-2013-2015/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
F7DR (INT LAMPS) Fuse B+B2545 01, B2545 04, B2615 02B2545 01, B2545 04, B2615 02
Courtesy Lamps Control - Terminal 2 X7B1480 0211
Dome Lamps ControlB2545 01, B2545 04, B2615 0222
Dome Lamp Ground2
Dome/Reading Lamps - Front Ground1, 2
Sunshade Mirror Lamp - Left Ground1
Sunshade Mirror Lamp - Right Ground1
1. Courtesy Lamps Malfunction 2. Dome Lamps Malfunction

The body control module (BCM) supplies battery voltage to the front reading lamps and left and right sunshade lamps via the courtesy lamp control circuit. When a sunshade mirror is opened, the switch contact close allowing battery voltage to flow illuminating the respective lamps. The front reading lamps are controlled by individual switches that are activated by the operator when additional cabin lighting is required. In the event that any of these courtesy lamps were to remain illuminated for more than 10 minutes with the vehicle ON/OFF switch in the OFF position and no doors opened, the BCM will deactivate the courtesy lamp control circuit to prevent total battery discharge.

Battery voltage must be between 9-16 V.

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

The BCM will disable the circuit and the sunshade lamps and front reading lamps will be inoperative.

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

Diagnostic Aids

When the F7DR (INT LAMPS) fuse is open, both dome lamps, sunshade lamps, reading lamps, and backup lamps will be inoperative. DTC B2545 will also set for the backup lamps when the vehicle is placed in the reverse gear.

Schematic Reference

  1. «Interior Lights Schematics»(/cadillac/elr/i-2013-2015/remont/exterior-lights/#lighting-system)
  2. «Body Control System Schematics»(/cadillac/elr/i-2013-2015/remont/communication-devices/#data-communication-system-schematic-wiring-diagrams)

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Vehicle OFF, exterior lamps OFF, disconnect the harness connectors at the components listed below. E37F dome/reading lamps - front E31L sunshade mirror lamp - left E31R sunshade mirror lamp - right
  2. Connect a test lamp between the appropriate control circuit terminal listed below and ground, vehicle in Service Mode. E37F dome/reading lamps - front terminal 1 E31L sunshade mirror lamp - left terminal A E31R sunshade mirror lamp - right terminal A
  3. Verify the test lamp turns ON and OFF when commanding the Inadvertent Load ON and OFF with a scan tool. If the test lamp is always OFF Vehicle OFF, disconnect the X7 harness connector at the K9 body control module. Test for infinite resistance between the control circuit and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance Test for less than 2 ohms in the control circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K9 body control module. If the test lamp is always ON Vehicle OFF, disconnect the X7 harness connector at the K9 body control module, vehicle in Service Mode. Test for less than 1 V between the control circuit terminal and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V, replace the K9 body control module. If the test lamp turns ON and OFF
  4. Test or replace the appropriate courtesy lamp.

Perform the Diagnostic Repair Verification after completing the repair.

  1. «Sunshade Replacement»(/cadillac/elr/i-2013-2015/remont/exteriorinterior-trim/#interior-trim-and-interior-paneling)
  2. «Center Reading and Courtesy Lamp Replacement»(/cadillac/elr/i-2013-2015/remont/exterior-lights/#lighting-system)
  3. «Control Module References»(/cadillac/elr/i-2013-2015/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM replacement, programming, and setup
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/elr/i-2013-2015/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/elr/i-2013-2015/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/elr/i-2013-2015/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 0011
Rear Fog Lamp ControlB2540 02B2540 041
Rear Fog Lamp Ground1
Turn Signal/Multifunction Switch Ground1
1. Rear Fog Lamp Malfunction

The rear fog lamp switch signal circuit is grounded momentarily by pressing the rear fog lamp switch. The body control module (BCM) responds to the rear fog lamp request by applying voltage to the rear fog lamp control circuit which illuminates the rear fog lamp.

  1. Battery voltage must be between 9-16 V.
  2. Rear fog lamp ON.

DTC B2540 02

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

DTC B2540 04

The BCM detects an open/high resistance in the rear fog lamp control circuit.

The rear fog lamp will not operate when the park lamps are ON and the rear 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 vehicle ON/OFF switch cycles have occurred.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Vehicle OFF, exterior lamps OFF, disconnect the harness connector at the E29R Fog Lamp - Rear.
  2. Test for less than 5 ohms between the ground circuit terminal 2 and ground. If 5 ohms or greater Vehicle OFF. Test for less than 2 ohms in the ground circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, repair the open/high resistance in the ground connection. If less than 5 ohms
  3. Connect a test lamp between the control circuit terminal 3 and ground, vehicle in Service Mode.
  4. Verify the test lamp turns ON and OFF when commanding the Rear Fog Lamp ON and OFF with a scan tool. If the test lamp is always OFF Vehicle OFF, disconnect the X6 harness connector at the K9 Body Control Module. Test for infinite resistance between the control circuit and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance Test for less than 2 ohms in the control circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K9 Body Control Module. If the test lamp is always ON Vehicle OFF, disconnect the X6 harness connector at the K9 Body Control Module, vehicle in Service Mode. Test for less than 1 V between the control circuit terminal and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V, replace the K9 Body Control Module. If the test lamp turns ON and OFF
  5. Test or replace the E29R Fog Lamp - Rear.

Perform the Diagnostic Repair Verification after completing the repair.

Control Module References for BCM replacement, programming, and setup

  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/elr/i-2013-2015/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/elr/i-2013-2015/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/elr/i-2013-2015/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
F7DR (INT LAMPS) Fuse B+B2545 01, B2545 04, B2615 02B2545 01, B2545 04, B2615 02
Backup Lamp ControlB2545 02B2545 01, B2545 041
Backup Lamp Ground1
1. Backup Lamps Malfunction

With the vehicle ON and the transmission 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 lamp control circuit illuminating the backup lamp. 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 vehicle must be ON for the backup lamps to operate.

  1. Battery voltage must be between 9-16 V.
  2. Vehicle ON.
  3. Transmission placed in REVERSE gear.

DTC B2545 01 and B2545 04

  1. The BCM detects an open/high resistance in the backup lamp control circuit.
  2. The BCM detects a short to ground or an open/high resistance in the F7DR fuse B+ circuit.

DTC B2545 02

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

The backup lamp 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 vehicle ON/OFF switch cycles have occurred.

Schematic Reference

  1. «Exterior Lights Schematics»(/cadillac/elr/i-2013-2015/remont/exterior-lights/#lighting-system)
  2. «Body Control System Schematics»(/cadillac/elr/i-2013-2015/remont/communication-devices/#data-communication-system-schematic-wiring-diagrams)

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Vehicle OFF, disconnect the X5 harness connector at the K9 body control module, vehicle in Service Mode.
  2. Verify a test lamp illuminates between the B+ circuit terminal 4 and ground. If the test lamp does not illuminate and the circuit fuse is good Vehicle OFF. Test for less than 2 ohms in the B+ circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, verify the fuse is not open and there is voltage at the fuse. If the test lamp does not illuminate and the circuit fuse is open Vehicle OFF. Test for infinite resistance between the B+ circuit and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance, replace the K9 body control module. If the test lamp illuminates
  3. Vehicle OFF, connect the X5 harness connector at the K9 body control module.
  4. Vehicle OFF, exterior lamps OFF, disconnect the harness connector at the E5 backup lamp.
  5. Test for less than 5 ohms between the ground circuit terminal and ground. If 5 ohms or greater Vehicle OFF. Test for less than 2 ohms in the ground circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, repair the open/high resistance in the ground connection. If less than 5 ohms
  6. Connect a test lamp between the control circuit terminal and ground, vehicle in Service Mode.
  7. Verify the test lamp turns ON and OFF when commanding the Backup Lamps ON and OFF with a scan tool. If the test lamp is always OFF Vehicle OFF, disconnect the X7 harness connector at the K9 body control module. Test for infinite resistance between the control circuit and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance Test for less than 2 ohms in the control circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K9 body control module. If the test lamp is always ON Vehicle OFF, disconnect the X7 harness connector at the K9 body control module, vehicle in Service Mode. Test for less than 1 V between the control circuit terminal and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V, replace the K9 body control module. If the test lamp turns ON and OFF
  8. Test or replace the E5 backup lamp.

Perform the Diagnostic Repair Verification after completing the repair.

  1. «Backup Lamp Bulb Replacement»(/cadillac/elr/i-2013-2015/remont/exterior-lights/#lighting-system)
  2. «Control Module References»(/cadillac/elr/i-2013-2015/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM replacement, programming, and setup
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/elr/i-2013-2015/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/elr/i-2013-2015/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/elr/i-2013-2015/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
F5DR (BCM/EXT LIGHTS) Fuse B+B270A 01B270A 01
Cargo Lamp ControlB2570 0211
Cargo Lamp Ground1
1. Rear Compartment Lamp Malfunction

The body control module (BCM) applies battery voltage to the cargo lamp through the rear cargo lamp control circuit. When the BCM receives a rear liftgate open input from the rear liftgate latch, the BCM applies battery voltage to the rear cargo lamp control circuit illuminating the cargo lamp. In the event that the cargo lamp were to remain illuminated for more than 10 minutes with the vehicle ON/OFF switch in the OFF position and no doors opened, the BCM will deactivate the cargo lamp control circuit to prevent total battery discharge.

  1. Battery voltage must be between 9-16 V.
  2. Liftgate OPEN.

The BCM detects a short to ground on the cargo lamp control circuit.

The cargo lamp is inoperative.

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

Schematic Reference

  1. «Interior Lights Schematics»(/cadillac/elr/i-2013-2015/remont/exterior-lights/#lighting-system)
  2. «Body Control System Schematics»(/cadillac/elr/i-2013-2015/remont/communication-devices/#data-communication-system-schematic-wiring-diagrams)

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Vehicle OFF, exterior lamps OFF, disconnect the harness connector at the E33 cargo lamp.
  2. Test for less than 5 ohms between the ground circuit terminal 2 and ground. If 5 ohms or greater Vehicle OFF. Test for less than 2 ohms in the ground circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, repair the open/high resistance in the ground connection. If less than 5 ohms
  3. Connect a test lamp between the control circuit terminal 1 and ground, vehicle in Service Mode.
  4. Verify the test lamp turns ON and OFF when commanding the Cargo Lamp ON and OFF with a scan tool. If the test lamp is always OFF Vehicle OFF, disconnect the X7 harness connector at the K9 body control module. Test for infinite resistance between the control circuit and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance Test for less than 2 ohms in the control circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K9 body control module. If the test lamp is always ON Vehicle OFF, disconnect the X7 harness connector at the K9 body control module, vehicle in Service Mode. Test for less than 1 V between the control circuit terminal and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V, replace the K9 body control module. If the test lamp turns ON and OFF
  5. Test or replace the E33 cargo lamp.

Perform the Diagnostic Repair Verification after completing the repair.

  1. «Rear Compartment Courtesy Lamp Replacement»(/cadillac/elr/i-2013-2015/remont/exterior-lights/#lighting-system)
  2. «Control Module References»(/cadillac/elr/i-2013-2015/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM replacement, programming, and setup
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/elr/i-2013-2015/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/elr/i-2013-2015/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/elr/i-2013-2015/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
Turn Signal/Multifunction Switch Park Lamps ON Signal2B257A 002
Turn Signal/Multifunction Switch Headlamps OFF SignalB257A 0011
Turn Signal/Multifunction Switch Headlamps ON SignalB257A 0011
Turn Signal/Multifunction Switch Ground1
1. Headlamps Malfunction 2. Park, License, and/or Tail Lamps Malfunction

For headlamp operation, the body control module (BCM) monitors three signal circuits from the turn signal/multifunction switch. When the turn signal/multifunction switch is in the AUTO position, the three signal circuits are open and the BCM relies on the ambient light sensor input to turn the headlamps and daytime running lamps (DRLs) ON and OFF. When the turn signal/multifunction switch is placed in the OFF position, the turn signal/multifunction switch headlamps OFF signal circuit is grounded, indicating to the BCM that the exterior lamps should be turned OFF. With the turn signal/multifunction switch in the PARK LAMPS position, the turn signal/multifunction switch park lamps ON signal circuit is grounded, indicating that the park lamps have been requested. When the turn signal/multifunction switch is in the HEADLAMP position, both the turn signal/multifunction switch park lamps ON signal circuit and the turn signal/multifunction switch headlamps ON signal circuit are grounded. The BCM responds by commanding the park lamps and headlamps ON.

Battery voltage must be between 9-16 V.

  1. The BCM detects an open/high resistance in the turn signal/multifunction switch park lamps ON signal circuit.
  2. The BCM detects a short to ground in the turn signal/multifunction switch headlamps ON signal circuit.
  3. The BCM detects a short to ground in the turn signal/multifunction switch headlamps OFF signal circuit.
  1. When DTC B257A 00 is present on the turn signal/multifunction switch headlamps OFF signal circuit, the low beam headlamps are always ON in the AUTO position. The turn signal/multifunction switch operates in all positions other than AUTO. The AUTO headlamp defeat is inoperative.
  2. When DTC B257A 00 is present on the turn signal/multifunction switch headlamps ON signal circuit, the low beam headlamps are always ON. The BCM disregards all turn signal/multifunction switch inputs.
  3. When DTC B257A 00 is present on the turn signal/multifunction switch park lamps ON signal circuit, the park lamps and low beam headlamps are inoperative in the PARK and HEAD positions. Headlamps and park lamps operate in AUTO position.
  1. The condition responsible for setting the DTC no longer exists.
  2. A history DTC will clear once 100 consecutive malfunction-free vehicle ON/OFF switch cycles have occurred.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Vehicle OFF, all doors closed, all accessories OFF, disconnect the harness connector at the S78 Turn Signal/Multifunction Switch. It may take up to 2 minutes for all vehicle systems to power down.
  2. Test for less than 10 ohms between the ground circuit terminal 6 and ground. If 10 ohms or greater Vehicle OFF. Test for less than 2 ohms in the ground circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, repair the open/high resistance in the ground connection. If less than 10 ohms
  3. Vehicle in Service Mode.
  4. Verify the scan tool Automatic Headlamps Disable Switch parameter is Inactive. If not Inactive Vehicle OFF, disconnect the X1 harness connector at the K9 Body Control Module. Test for infinite resistance between the signal circuit terminal 9 and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance, replace the K9 Body Control Module. If Inactive
  5. Install a 3 A fused jumper wire between the signal circuit terminal 9 and ground.
  6. Verify the scan tool Automatic Headlamps Disable Switch parameter is Active. If not Active Vehicle OFF, disconnect the X1 harness connector at the K9 Body Control Module, vehicle in Service Mode. Test for less than 1 V between the signal circuit terminal 9 and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V Test for less than 2 ohms in the signal circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K9 Body Control Module. If Active
  7. Verify the scan tool Park Lamps Switch parameter is Inactive. If not Inactive Vehicle OFF, disconnect the X1 harness connector at the K9 Body Control Module. Test for infinite resistance between the signal circuit terminal 7 and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance, replace the K9 Body Control Module. If Inactive
  8. Install a 3 A fused jumper wire between the signal circuit terminal 7 and ground.
  9. Verify the scan tool Park Lamps Switch parameter is Active. If not Active Vehicle OFF, disconnect the X1 harness connector at the K9 Body Control Module, vehicle in Service Mode. Test for less than 1 V between the signal circuit terminal 7 and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V Test for less than 2 ohms in the signal circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K9 Body Control Module. If Active
  10. Verify the scan tool Headlamps On Switch parameter is Inactive. If not Inactive Vehicle OFF, disconnect the X1 harness connector at the K9 Body Control Module. Test for infinite resistance between the signal circuit terminal 2 and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance, replace the K9 Body Control Module. If Inactive
  11. Install a 3 A fused jumper wire between the signal circuit terminal 2 and ground.
  12. Verify the scan tool Headlamps On Switch parameter is Active. If not Active Vehicle OFF, disconnect the X1 harness connector at the K9 Body Control Module, vehicle in Service Mode. Test for less than 1 V between the signal circuit terminal 2 and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V Test for less than 2 ohms in the signal circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K9 Body Control Module. If Active
  13. Test or replace the S78 Turn Signal/Multifunction Switch.

Perform the Diagnostic Repair Verification after completing the repair.

  1. «Turn Signal Switch Replacement»(/cadillac/elr/i-2013-2015/remont/steering-column-switches/#steering-wheel-and-steering-column)
  2. «Control Module References»(/cadillac/elr/i-2013-2015/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM replacement, programming, and setup
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/elr/i-2013-2015/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/elr/i-2013-2015/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/elr/i-2013-2015/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 High Beam Relay ControlB2580 02, B2580 04B2580 02, B2580 04B2580 01
High Beam Headlamp Control - Left111
High Beam Headlamp Control - Right111
Headlamp Ground - Left1
Headlamp Ground - Right1
1. Headlamps Malfunction

The high beam and flash to pass functions are contained within the turn signal/multifunction switch. The BCM provides the turn signal/multifunction switch with two signal circuits, the high beam signal circuit and the flash to pass signal circuit. When the low beam headlamps are ON and the turn signal/multifunction switch is placed in the high beam position, ground is applied to the BCM through the high beam signal circuit. The BCM responds to the high beam request by applying ground to the 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 high beam fuses to the high beam control circuits illuminating the high beam headlamps.

  1. Battery voltage must be between 9-16 V.
  2. High beam headlamps ON.

DTC B2580 01

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

DTC B2580 02 and B2580 04

The BCM detects a short to ground or an open/high resistance in the headlamp high beam relay control circuit.

  1. For an open/high resistance fault, the high beam headlamps and flash to pass function are inoperative. The high beam indicator on the instrument cluster operates normally.
  2. For a short to ground fault, the high beam headlamps and high beam indicator on the instrument cluster are always ON with the headlamp switch in the AUTO or HEAD positions.
  3. For a short to voltage fault, the high beam headlamps and flash to pass function are inoperative.
  1. The condition responsible for setting the DTC no longer exists.
  2. A history DTC will clear once 100 consecutive malfunction-free vehicle ON/OFF switch cycles have occurred.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Vehicle OFF, disconnect the X2 harness connector at the X50A fuse block - underhood.
  2. Connect a test lamp between the control circuit terminal 18 and B+, vehicle in Service Mode.
  3. Verify the test lamp turns ON and OFF when commanding the High Beams ON and OFF with a scan tool. If the test lamp is always OFF Vehicle OFF, disconnect the X5 harness connector at the K9 body control module, vehicle in Service Mode. Test for less than 1 V between the control circuit terminal and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V Vehicle OFF. Test for less than 2 ohms in the control circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K9 body control module. If the test lamp is always ON Vehicle OFF, disconnect the X5 harness connector at the K9 body control module. Test for infinite resistance between the control circuit terminal and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance, replace the K9 body control module. If the test lamp turns ON and OFF
  4. Test or replace the X50A fuse block - underhood.

Perform the Diagnostic Repair Verification after completing the repair.

  1. «Accessory Wiring Junction Block Replacement»(/cadillac/elr/i-2013-2015/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-repair-instructions)
  2. «Control Module References»(/cadillac/elr/i-2013-2015/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM replacement, programming, and setup
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/elr/i-2013-2015/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/elr/i-2013-2015/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/elr/i-2013-2015/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
F6DR (APO/EXT LIGHTS) Fuse B+B3867 01, B3867 04, B3949 01, B3949 04B3867 01, B3867 04, B3949 01, B3949 04
Turn Signal/Multifunction Switch Park Lamps ON Signal2B257A 002
License Plate Lamp ControlB3883 02B3883 01, B3883 04B3883 01
Park Lamps Control - Left FrontB2585 02B2585 01, B2585 04B2585 01, B2585 04
Park Lamps Control - Right FrontB3867 02B3867 01, B3867 04B3867 01, B3867 04
Park Lamps Control - Left Rear111
Park Lamps Control - Right Rear111
License Plate Lamp Ground - Right1
License Plate Lamp Ground - Left1
Park Lamp Ground - Left FrontB2585 01, B2585 04, B3948 01, B3948 04
Park Lamp Ground - Right FrontB3867 01, B3867 04, B3949 01, B3949 04
Tail Lamp Ground - Left1
Tail Lamp Ground - Right1
Turn Signal/Multifunction Switch Ground2
1. Park, License, and/or Tail Lamps Malfunction 2. Park Lamp Switch Malfunction

When the turn signal/multifunction switch is placed in the HEAD or PARK position, ground is applied to the park lamps ON signal circuit to the body control module (BCM). The BCM responds by applying voltage to the park lamps, tail lamps, and license lamps control circuits illuminating the park, tail, and license lamps.

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

DTC B2585 01 and B2585 04

  1. The BCM detects a short to voltage or an open/high resistance in the left front park lamp control circuit.
  2. The BCM detects an open/high resistance in the left front park lamp ground circuit.

DTC B2585 02

The BCM detects a short to ground in the left front park lamp control circuit.

DTC B3867 01 and B3867 04

  1. The BCM detects a short to voltage or an open/high resistance in the right front park lamp control circuit.
  2. The BCM detects an open/high resistance in the right front park lamp ground circuit.
  3. The BCM detects a short to ground or an open/high resistance in the F6DR (APO/EXT LIGHTS) fuse B+ circuit.

DTC B3867 02

The BCM detects a short to ground in the right front park lamp control circuit.

DTC B2585 01

The left front park lamp is always ON.

DTC B2585 02 and B2585 04

The left front park lamp is inoperative.

DTC B3867 01

The right front park lamp is always ON.

DTC B3867 02 and B3867 04

  1. The right front park lamp is inoperative.
  2. When the F6DR (APO/EXT LIGHTS) fuse is open, the left rear park lamp and right front park lamp are inoperative.
  1. The condition responsible for setting the DTC no longer exists.
  2. A history DTC will clear once 100 consecutive malfunction-free vehicle ON/OFF switch cycles have occurred.

Schematic Reference

  1. «Exterior Lights Schematics»(/cadillac/elr/i-2013-2015/remont/exterior-lights/#lighting-system)
  2. «Body Control System Schematics»(/cadillac/elr/i-2013-2015/remont/communication-devices/#data-communication-system-schematic-wiring-diagrams)

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

DTC B2585

  1. Vehicle OFF, exterior lamps OFF, disconnect the harness connector at the E4N park/turn signal lamp - left.
  2. Test for less than 5 ohms between the ground circuit terminal 1 and ground. If 5 ohms or greater Vehicle OFF. Test for less than 2 ohms in the ground circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, repair the open/high resistance in the ground connection. If less than 5 ohms
  3. Connect a test lamp between the control circuit terminal 2 and ground, vehicle in Service Mode.
  4. Verify the test lamp turns ON and OFF when commanding the Left Front Park Lamp ON and OFF with a scan tool. If the test lamp is always OFF Vehicle OFF, disconnect the X4 harness connector at the K9 body control module. Test for infinite resistance between the control circuit and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance Test for less than 2 ohms in the control circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K9 body control module. If the test lamp is always ON Vehicle OFF, disconnect the X4 harness connector at the K9 body control module, vehicle in Service Mode. Test for less than 1 V between the control circuit terminal and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V, replace the K9 body control module. If the test lamp turns ON and OFF
  5. Test or replace the E4N park/turn signal lamp - left.

DTC B3867

  1. Vehicle OFF, exterior lamps OFF, disconnect the harness connector at the E4P park/turn signal lamp - right.
  2. Test for less than 5 ohms between the appropriate ground circuit terminal 1 and ground. If 5 ohms or greater Vehicle OFF. Test for less than 2 ohms in the ground circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, repair the open/high resistance in the ground connection. If less than 5 ohms
  3. Connect a test lamp between the control circuit terminal 2 and ground, vehicle in Service Mode.
  4. Verify the test lamp turns ON and OFF when commanding the Right Front Park Lamp ON and OFF with a scan tool. If the test lamp is always OFF Vehicle OFF, disconnect the X4 harness connector at the K9 body control module. Test for infinite resistance between the control circuit and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance Test for less than 2 ohms in the control circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K9 body control module. If the test lamp is always ON Vehicle OFF, disconnect the X4 harness connector at the K9 body control module, vehicle in Service Mode. Test for less than 1 V between the control circuit terminal and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V, replace the K9 body control module. If the test lamp turns ON and OFF
  5. Test or replace the E4P park/turn signal lamp - right.

Perform the Diagnostic Repair Verification after completing the repair.

Control Module References for BCM replacement, programming, and setup

  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/elr/i-2013-2015/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/elr/i-2013-2015/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/elr/i-2013-2015/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
Ambient Light Sensor Low Reference1B2645 07, B0163 05, B0183 051
Daytime Running Lamp Control - LeftB2600 0211
Daytime Running Lamp Control - RightB2605 0211
Daytime Running Lamp Ground - Left1
Daytime Running Lamp Ground - Right1
1. 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 volts depending on outside lighting conditions. The body control module (BCM) provides a 5-volt reference signal to the ambient light sensor and the HVAC control module provides a low reference ground. The BCM monitors the ambient light sensor signal circuit to determine if outside lighting conditions are correct for either daytime running lights (DRL) or the automatic headlamp system when the headlamp switch is in the AUTO position. In daylight conditions, the BCM will command the DRLs ON by applying voltage to the left and right DRL control circuits illuminating the DRLs. Any function or condition that turns on the headlamps will cancel DRL operation.

Battery voltage must be between 9-16 V.

DTC B2600 02

The BCM detects a short to ground in the left daytime running lamp control circuit.

DTC B2605 02

The BCM detects a short to ground in the right daytime running lamp control circuit.

DTC B2600 02

The left daytime running lamp is inoperative.

DTC B2605 02

The right daytime running lamp is inoperative.

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

The daytime running lamps will only operate in daylight conditions with the vehicle ON and in any transmission gear except PARK.

Schematic Reference

  1. «Headlights/Daytime Running Lights (DRL) Schematics»(/cadillac/elr/i-2013-2015/remont/exterior-lights/#lighting-system)
  2. «Body Control System Schematics»(/cadillac/elr/i-2013-2015/remont/communication-devices/#data-communication-system-schematic-wiring-diagrams)

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Vehicle OFF, exterior lamps OFF, disconnect the harness connector at the inoperative E4 Park/Daytime Running Lamp - Lower.
  2. Test for less than 5 ohms between the ground circuit terminal C and ground. If 5 ohms or greater Vehicle OFF. Test for less than 2 ohms in the ground circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, repair the open/high resistance in the ground connection. If less than 5 ohms
  3. Connect a test lamp between the control circuit terminal B and ground, vehicle ON.
  4. Verify the test lamp turns ON and OFF when commanding the appropriate Park/Daytime Running Lamp ON and OFF with a scan tool. If the test lamp is always OFF Vehicle OFF, disconnect the appropriate harness connector listed below at the K9 Body Control Module. X4 - left daytime running lamp X7 - right daytime running lamp Test for infinite resistance between the control circuit and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance Test for less than 2 ohms in the control circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K9 Body Control Module. If the test lamp is always ON Vehicle OFF, disconnect the appropriate harness connector listed below at the K9 Body Control Module, vehicle ON. X4 - left daytime running lamp X7 - right daytime running lamp Test for less than 1 V between the control circuit terminal and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V, replace the K9 Body Control Module. If the test lamp turns ON and OFF
  5. Test or replace the E4 Park/Daytime Running Lamp - Lower.

Perform the Diagnostic Repair Verification after completing the repair.

  1. «Headlamp Replacement»(/cadillac/elr/i-2013-2015/remont/exterior-lights/#lighting-system)
  2. «Control Module References»(/cadillac/elr/i-2013-2015/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM replacement, programming, and setup
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/elr/i-2013-2015/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/elr/i-2013-2015/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/elr/i-2013-2015/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
LED Backlight Dimming Control Terminal 8 X2B2610 02B2610 04, 1B2610 01, 1
LED Backlight Dimming Control Terminal 9 X7B2610 02B2610 04, 1B2610 01, 1
1. Interior Backlighting Malfunction

The instrument panel dimmer switch is used to increase and decrease the brightness of the interior backlighting components. The instrument panel dimmer switch provides a voltage signal to the body control module (BCM) that will increase as the brightness of the lights are increased and decrease as the brightness of the lights are decreased. The BCM provides a B+, low reference, and signal circuits to the instrument panel dimmer switch. When the instrument panel dimmer switch is placed in the desired position, the dimmed voltage setting is applied from the instrument panel dimmer switch through the instrument panel dimmer switch signal circuit to the BCM. The BCM interprets the signal and applies a pulse width modulated (PWM) voltage through the LED dimming control circuits illuminating the interior backlighting to the requested level of brightness.

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

DTC B2610 01

The BCM detects a short to battery in the LED backlight dimming control circuit terminal 8 X2 or the LED backlight dimming control circuit terminal 9 X7.

DTC B2610 02

The BCM detects a short to ground in the LED backlight dimming control circuit terminal 8 X2 or the LED backlight dimming control circuit terminal 9 X7.

DTC B2610 04

The BCM detects an open/high resistance in the LED backlight dimming control circuit terminal 8 X2 or the LED backlight dimming control circuit terminal 9 X7.

The BCM will disable the LED backlight dimming control circuits.

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

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Vehicle OFF, all doors closed, all accessories OFF, disconnect the harness connector at the component with inoperative backlighting. It may take up to 2 minutes for all vehicle systems to power down.
  2. Test for less than 15 ohms between the appropriate ground circuit terminal listed below and ground. E37F dome/reading lamps - front - terminal 6 S16 driver information center switch - terminal 4 S25 garage door opener switch - terminal 3 S48B multifunction switch - overhead console - terminal 2 S52 outside rearview mirror switch - terminal 11 S70R steering wheel controls switch - right - terminal 5 S70L steering wheel controls switch - left - terminal 7 S91 park brake control switch - terminal 8 S83 vehicle ON/OFF switch - terminal 4 S113 charge port door open request switch - terminal 4 S117 refuel request switch - terminal 4 If 15 ohms or greater Vehicle OFF. Test for less than 2 ohms in the ground circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, repair the open/high resistance in the ground connection. If less than 15 ohms
  3. Connect a test lamp between the appropriate control circuit terminal listed below and ground. E37F dome/reading lamps - front - terminal 3 S16 driver information center switch - terminal 3 S25 garage door opener switch - terminal 2 S48B multifunction switch - overhead console - terminal 1 S52 outside rearview mirror switch - terminal 1 S70R steering wheel controls switch - right - terminal 4 S70L steering wheel controls switch - left - terminal 6 S83 vehicle ON/OFF switch - terminal 8 S91 park brake control switch - terminal 6 S113 charge port door open request switch - terminal 5 S117 refuel request switch - terminal 5
  4. Verify the test lamp turns ON and OFF when commanding the LED Backlight Dimming ON and OFF with a scan tool. If the test lamp is always OFF Vehicle OFF, disconnect the X2 and X7 harness connectors at the K9 body control module. Test for infinite resistance between the control circuit and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance Test for less than 2 ohms in the control circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K9 body control module. If the test lamp is always ON Vehicle OFF, disconnect the X2 and X7 harness connectors at the K9 body control module, vehicle in Service Mode Test for less than 1 V between the control circuit terminal and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V, replace the K9 body control module. If the test lamp turns ON and OFF
  5. Test or replace the component with inoperative backlighting.

Perform the Diagnostic Repair Verification after completing the repair.

  1. «Outside Rearview Mirror Remote Control Switch Replacement»(/cadillac/elr/i-2013-2015/remont/mirrors/#mirror-system)
  2. «Radio Control Assembly Replacement»(/cadillac/elr/i-2013-2015/remont/entertainment-systems/#cellular-system-entertainment-system-and-navigation-system)
  3. «Garage Door Opener Transmitter Pushbutton Replacement»(/cadillac/elr/i-2013-2015/remont/door-locks-anti-theft-systems/#keyless-entry-system-and-remote-functions)
  4. «Parking Brake Switch Replacement»(/cadillac/elr/i-2013-2015/remont/parking-brake-system/#parking-brake-system)
  5. «Fuel Tank Filler Door Lock Release Switch Replacement»(/cadillac/elr/i-2013-2015/remont/door-locks-anti-theft-systems/#power-door-lock-system-and-release-systems)
  6. «Control Module References»(/cadillac/elr/i-2013-2015/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM replacement, programming, and setup
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/elr/i-2013-2015/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/elr/i-2013-2015/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/elr/i-2013-2015/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
F7DR (INT LAMPS) Fuse B+B2545 01, B2545 04, B2615 02B2545 01, B2545 04, B2615 02
Dome Lamps ControlB2545 01, B2545 04, B2615 0211
Dome Lamp - Front Ground1
Dome Lamp - Middle Ground1
1. Dome Lamps Malfunction

The dome lamp switch has 3 positions: DOOR, OFF, and ON. The ON position provides a ground for continuous operation and the dome lamps will remain illuminated until the switch is placed in either the DOOR or OFF position. When in the DOOR position, the dome lamps operation is controlled by the body control module (BCM). When any door is opened, the door ajar switch contacts close and the BCM receives a door-open input. The BCM illuminates the dome lamps when any door is opened or a door lock/unlock request is activated with the key fob. After all doors have been closed, the dome lamps will remain illuminated approximately 3 seconds after the last door closes. When the driver places the dome lamp switch in the OFF position, the dome lamps will be disabled. In the event that the dome lamps were to remain illuminated for more than 10 minutes with the vehicle ON/OFF switch in the OFF position and no doors opened, the BCM will deactivate the dome lamps control circuit to prevent total battery discharge.

Battery voltage must be between 9-16 V.

  1. The BCM detects a short to ground in the dome lamps control circuit.
  2. The BCM detects a short to ground or an open/high resistance in the F7DR (INT LAMPS) fuse B+ circuit.

The front and middle dome lamps are inoperative.

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

When the F7DR (INT LAMPS) fuse is open, both dome lamps, sunshade lamps, reading lamps, and backup lamps will be inoperative. DTC B2545 will also set for the backup lamps when the vehicle is placed in the reverse gear.

Schematic Reference

  1. «Interior Lights Schematics»(/cadillac/elr/i-2013-2015/remont/exterior-lights/#lighting-system)
  2. «Body Control System Schematics»(/cadillac/elr/i-2013-2015/remont/communication-devices/#data-communication-system-schematic-wiring-diagrams)

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Vehicle OFF, disconnect the X5 harness connector at the K9 body control module, vehicle in Service Mode.
  2. Verify a test lamp illuminates between the B+ circuit terminal 4 and ground. If the test lamp does not illuminate and the circuit fuse is good Vehicle OFF. Test for less than 2 ohms in the B+ circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, verify the fuse is not open and there is voltage at the fuse. If the test lamp does not illuminate and the circuit fuse is open Vehicle OFF. Test for infinite resistance between the B+ circuit and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance, replace the K9 body control module. If the test lamp illuminates
  3. Vehicle OFF, connect the X5 harness connector at the K9 body control module.
  4. Vehicle OFF, scan tool disconnected, all doors closed, all accessories OFF, disconnect the harness connector at the E37F dome/reading lamps - front and E36AH dome lamp - middle. It may take up to 2 minutes for all vehicle systems to power down.
  5. Test for less than 10 ohms between the ground circuit terminals listed below and ground. E37F dome reading lamps - front terminal 6 E36AH dome lamp - middle terminal 6 If 10 ohms or greater Vehicle OFF. Test for less than 2 ohms in the ground circuits end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, repair the open/high resistance in the ground connection. If less than 10 ohms
  6. Connect a test lamp between the control circuit terminals listed below and ground. E37F dome reading lamps - front terminal 2 E36AH dome lamp - middle terminal 2
  7. Verify the test lamp turns ON and OFF when commanding the Courtesy Lamps ON and OFF with a scan tool. If the test lamp is always OFF Vehicle OFF, disconnect the X7 harness connector at the K9 body control module. Test for infinite resistance between the control circuit and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance Test for less than 2 ohms in the control circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K9 body control module. If the test lamp is always ON Vehicle OFF, disconnect the X7 harness connector at the K9 body control module, vehicle in Service Mode. Test for less than 1 V between the control circuit terminal and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V, replace the K9 body control module. If the test lamp turns ON and OFF
  8. Test or replace the inoperative dome/reading lamp.

Perform the Diagnostic Repair Verification after completing the repair.

  1. «Dome and Reading Lamp Switch Replacement»(/cadillac/elr/i-2013-2015/remont/exterior-lights/#lighting-system)
  2. «Center Reading Lamp Replacement»(/cadillac/elr/i-2013-2015/remont/exterior-lights/#lighting-system)
  3. «Center Reading and Courtesy Lamp Replacement»(/cadillac/elr/i-2013-2015/remont/exterior-lights/#lighting-system)
  4. «Control Module References»(/cadillac/elr/i-2013-2015/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM replacement, programming, and setup
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/elr/i-2013-2015/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/elr/i-2013-2015/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/elr/i-2013-2015/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 Assist Switch Amber LED Backlight Dimming Control Terminal 5 X1B2625 0211
Multifunction Switch - Overhead Console Ground1
1. Interior Backlighting Malfunction

The instrument panel dimmer switch is used to increase and decrease the brightness of the interior backlighting components. The instrument panel dimmer switch provides a voltage signal to the body control module (BCM) that will increase as the brightness of the lights are increased and decrease as the brightness of the lights are decreased. The BCM provides a B+, low reference, and signal circuits to the instrument panel dimmer switch. When the instrument panel dimmer switch is placed in the desired position, the dimmed voltage setting is applied from the instrument panel dimmer switch through the instrument panel dimmer switch signal circuit to the BCM. The BCM interprets the signal and applies a pulse width modulated (PWM) voltage through the garage door opener switch amber LED indicator control circuit illuminating the garage door opener switch amber LED to the requested level of brightness.

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

The BCM detects a short to ground in the park assist switch amber LED backlight dimming control circuit terminal 5 X1.

The park assist switch amber LED is inoperative.

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

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Vehicle OFF, disconnect the harness connector at the S48B Multifunction Switch - Overhead Console.
  2. Connect a test lamp between the control circuit terminal 3 and ground.
  3. Verify the test lamp turns ON and OFF when commanding the LED Backlight Dimming ON and OFF with a scan tool. If the test lamp is always OFF Vehicle OFF, disconnect the X1 harness connector at the K9 Body Control Module. Test for infinite resistance between the control circuit and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance Test for less than 2 ohms in the control circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K9 Body Control Module. If the test lamp is always ON Vehicle OFF, disconnect the X1 harness connector at the K9 Body Control Module., vehicle in Service Mode. Test for less than 1 V between the control circuit terminal and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V, replace the K9 Body Control Module. If the test lamp turns ON and OFF
  4. Vehicle OFF.
  5. Connect a test lamp between the control circuit terminal 3 and low reference circuit terminal 2.
  6. Verify the test lamp turns ON and OFF when commanding the LED Backlight Dimming ON and OFF with a scan tool. If the test lamp is always OFF Vehicle OFF, disconnect the X1 harness connector at the K41 Front and Rear Parking Assist Control Module, vehicle in Service Mode. Test for less than 1 V between the low reference circuit terminal and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V Test for less than 2 ohms in the low reference circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K41 Front and Rear Parking Assist Control Module, vehicle in Service Mode. If the test lamp turns ON and OFF
  7. Test or replace the S48B Multifunction Switch - Overhead Console.

Perform the Diagnostic Repair Verification after completing the repair.

Control Module References for BCM replacement, programming, and setup

  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/elr/i-2013-2015/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/elr/i-2013-2015/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/elr/i-2013-2015/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
Daytime Running Lamp Control - Left222
Daytime Running Lamp Control - Right222
Low Beam Headlamp Control - Left111
Low Beam Headlamp Control - Right111
Ambient Light Sensor Low Reference2B2645 07, B0163 05, B0183 052
Daytime Running Lamp Ground - Left2
Daytime Running Lamp Ground - Right2
Headlamp Ground - Left1
Headlamp Ground - Right1
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 volts depending on outside lighting conditions. The body control module (BCM) provides a 5-volt reference signal to the ambient light sensor and the HVAC control module provides a low reference ground. The BCM monitors the ambient light sensor signal circuit to determine if outside lighting conditions are correct for either daytime running lights (DRL) or the automatic headlamp system when the headlamp switch is in the AUTO position. In daylight conditions, the BCM will command the DRLs ON by applying voltage to the left and right DRL control circuits illuminating the DRLs. Any function or condition that turns on the headlamps will cancel DRL operation.

Battery voltage must be between 9-16 V.

DTC B2645 03

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

DTC B2645 07

  1. The BCM detects a short to voltage or an open/high resistance in the ambient light sensor signal circuit.
  2. The BCM detects an open/high resistance in the ambient light sensor low reference circuit.
  1. Automatic headlamp system and daytime running lamps are 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 vehicle ON/OFF switch cycles have occurred.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Vehicle OFF, scan tool disconnected, all doors closed, all accessories OFF, open and close drivers door, disconnect the harness connector at the B10B ambient light/sunload sensor. It may take up to 2 minutes for all vehicle systems to power down.
  2. Test for less than 15 ohms between the low reference circuit terminal 6 and ground. If 15 ohms or greater Vehicle OFF, disconnect the X1 harness connector at the K33 HVAC control module, vehicle in Service Mode. Test for less than 1 V between the low reference circuit terminal 6 and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V Test for less than 2 ohms in the low reference circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K33 HVAC control module. If less than 15 ohms
  3. Vehicle in Service Mode.
  4. Verify the scan tool Ambient Light Sensor parameter is greater than 4.65 V. If 4.65 V or less Vehicle OFF, disconnect the X2 harness connector at the K9 body control module. Test for infinite resistance between the signal circuit terminal 5 and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance, replace the K9 body control module. If greater than 4.65 V
  5. Install a 3 A fused jumper wire between the signal circuit terminal 5 and the low reference circuit terminal 6.
  6. Verify the scan tool Ambient Light Sensor parameter is less than 0.196 V. If 0.196 V or greater Vehicle OFF, disconnect the X2 harness connector at the K9 body control module, vehicle in Service Mode. Test for less than 1 V between the signal circuit terminal 5 and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V Test for less than 2 ohms in the signal circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K9 body control module. If less than 0.196 V
  7. Test or replace the B10B ambient light/sunload sensor.

Perform the Diagnostic Repair Verification after completing the repair.

  1. «Sun Load Temperature and Headlamp Automatic Control Ambient Light Sensor Replacement»(/cadillac/elr/i-2013-2015/remont/automatic-hvac-system/#hvac-system-automatic)
  2. «Control Module References»(/cadillac/elr/i-2013-2015/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM or HVAC control module replacement, programming, and setup
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/elr/i-2013-2015/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/elr/i-2013-2015/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/elr/i-2013-2015/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 0011
Rear Fog Lamp ControlB2540 02B2540 041
Rear Fog Lamp Ground1
Turn Signal/Multifunction Switch Ground1
1. Rear Fog Lamp Malfunction

The rear fog lamp switch signal circuit is grounded momentarily by pressing the rear fog lamp switch. The body control module (BCM) responds to the rear fog lamp request by applying voltage to the rear fog lamp control circuit which illuminates the rear fog lamp.

Battery voltage must be between 9-16 V.

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

The rear fog lamp indicator on the instrument cluster is always ON.

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

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Vehicle OFF, scan tool disconnected, all doors closed, all accessories OFF, disconnect the harness connector at the S78 Turn Signal/Multifunction Switch. It may take up to 2 minutes for all vehicle systems to power down.
  2. Test for less than 15 ohms between the ground circuit terminal 6 and ground. If 15 ohms or greater Vehicle OFF. Test for less than 2 ohms in the ground circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, repair the open/high resistance in the ground connection. If less than 15 ohms
  3. Vehicle in Service Mode.
  4. Verify the scan tool Rear Fog Lamp Switch parameter is Inactive. If not Inactive Vehicle OFF, disconnect the X1 harness connector at the K9 Body Control Module. Test for infinite resistance between the signal circuit terminal 1 and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance, replace the K9 Body Control Module. If Inactive
  5. Install a 3 A fused jumper wire between the signal circuit terminal 1 and ground.
  6. Verify the scan tool Rear Fog Lamp Switch parameter is Active. If not Active Vehicle OFF, disconnect the X1 harness connector at the K9 Body Control Module, vehicle in Service Mode. Test for less than 1 V between the signal circuit terminal 1 and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V Test for less than 2 ohms in the signal circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K9 Body Control Module. If Active
  7. Test or replace the S78 Turn Signal/Multifunction Switch.

Perform the Diagnostic Repair Verification after completing the repair.

  1. «Turn Signal Switch Replacement»(/cadillac/elr/i-2013-2015/remont/steering-column-switches/#steering-wheel-and-steering-column)
  2. «Control Module References»(/cadillac/elr/i-2013-2015/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM replacement, programming, and setup
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/elr/i-2013-2015/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/elr/i-2013-2015/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/elr/i-2013-2015/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 Warning Switch Signal111B3596 00
Hazard Warning Switch Ground1
1. Hazard Lamps Malfunction

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

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

The hazard warning switch input is Active for longer than 60 seconds.

The hazard lamps are inoperative.

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

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Vehicle OFF, scan tool disconnected, all doors closed, all accessories OFF, disconnect the harness connector at the A20 radio/HVAC controls. It may take up to 2 minutes for all vehicle systems to power down.
  2. Test for less than 5 ohms between the ground circuit terminal 17 and ground. If 5 ohms or greater Vehicle OFF. Test for less than 2 ohms in the ground circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, repair the open/high resistance in the ground connection. If less than 5 ohms
  3. Vehicle in Service Mode.
  4. Verify the scan tool Hazard Lamps Switch parameter is Inactive. If not Inactive Vehicle OFF, disconnect the X2 harness connector at the K9 body control module. Test for infinite resistance between the signal circuit terminal 16 and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance, replace the K9 body control module. If Inactive
  5. Install a 3 A fused jumper wire between the signal circuit terminal 16 and the ground terminal 17.
  6. Verify the scan tool Hazard Lamps Switch parameter is Active. If not Active Vehicle OFF, disconnect the X2 harness connector at the K9 body control module, vehicle in Service Mode. Test for less than 1 V between the signal circuit terminal 1 and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V Test for less than 2 ohms in the signal circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K9 body control module. If Active
  7. Test or replace the A20 radio/HVAC controls.

Perform the Diagnostic Repair Verification after completing the repair.

  1. «Radio Control Assembly Replacement»(/cadillac/elr/i-2013-2015/remont/entertainment-systems/#cellular-system-entertainment-system-and-navigation-system)
  2. «Control Module References»(/cadillac/elr/i-2013-2015/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM replacement, programming, and setup
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/elr/i-2013-2015/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/elr/i-2013-2015/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/elr/i-2013-2015/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
Instrument Panel Dimmer Switch B+B1395 03, B3600 03B3600 031B1395 07, 1
Instrument Panel Dimmer Switch SignalB3600 03B3600 03B3600 07, 1
LED Backlight Dimming Control Terminal 8 X2B2610 02B2610 04, 1B2610 01, 1
LED Backlight Dimming Control Terminal 9 X7B2610 02B2610 04, 1B2610 01, 1
Instrument Panel Dimmer Switch Low Reference111
Driver Information Center Switch Ground1
1. Interior Backlighting Malfunction

The instrument panel dimmer switch is used to increase and decrease the brightness of the interior backlighting components. The instrument panel dimmer switch provides a voltage signal to the body control module (BCM) that will increase as the brightness of the lights are increased and decrease as the brightness of the lights are decreased. The BCM provides B+, low reference, and signal circuits to the instrument panel dimmer switch. When the instrument panel dimmer switch is placed in the desired position, the dimmed voltage setting is applied from the instrument panel dimmer switch through the instrument panel dimmer switch signal circuit to the BCM. The BCM interprets the signal and applies a pulse width modulated (PWM) voltage through the LED dimming control circuits illuminating the interior backlighting to the requested level of brightness.

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

DTC B3600 03

  1. The BCM detects a short to ground or an open/high resistance in the instrument panel dimmer switch B+ reference circuit.
  2. The BCM detects a short to ground or an open/high resistance in the instrument panel dimmer switch signal circuit.

DTC B3600 07

The BCM detects a short to voltage in the instrument panel dimmer switch signal circuit.

The interior backlighting defaults to FULL bright.

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

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Vehicle OFF, disconnect the harness connector at the S36 Instrument Panel dimmer Switch, vehicle in Service Mode.
  2. Verify a test lamp illuminates between the low reference circuit terminal 1 and B+. If the test lamp does not illuminate Vehicle OFF, disconnect the X1 harness connector at the K9 Body Control Module, vehicle in Service Mode. Test for less than 1 V between the low reference circuit terminal 1 and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V Test for less than 2 ohms in the low reference circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K9 Body Control Module If the test lamp illuminates
  3. Test for B+ between the B+ circuit terminal 6 and ground. If less than B+ Vehicle OFF, disconnect the X1 harness connector at the K9 Body Control Module Test for infinite resistance between the B+ reference circuit and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance Test for less than 2 ohms in the B+ reference circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K9 Body Control Module If B+
  4. Verify a test lamp does not illuminate between the B+ circuit terminal 6 and ground. If the test lamp illuminates Vehicle OFF, disconnect the X1 harness connector at the K9 Body Control Module, vehicle in Service Mode. Test for less than 1 V between the B+ circuit terminal 6 and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V, replace the K9 Body Control Module If the test lamp does not illuminate
  5. Verify the scan tool LED Backlight Dimming Command parameter is greater than 40%. If 40% or less Vehicle OFF, disconnect the X2 harness connector at the K9 Body Control Module, vehicle in Service Mode. Test for less than 1 V between the signal circuit terminal 2 and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V, replace the K9 Body Control Module. If greater than 40%
  6. Install a 3 A fused jumper wire between the signal circuit terminal 2 and the B+ circuit terminal 6.
  7. Verify the scan tool LED Backlight Dimming Command parameter is less than 30%. If 30% or greater Vehicle OFF, disconnect the X2 harness connector at the K9 Body Control Module Test for infinite resistance between the signal circuit and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance Test for less than 2 ohms in the signal circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K9 Body Control Module If less than 30%
  8. Test or replace the S36 Instrument Panel dimmer Switch.

Perform the Diagnostic Repair Verification after completing the repair.

  1. «Interior Lamp Switch Replacement (Reading Lamp)»(/cadillac/elr/i-2013-2015/remont/exterior-lights/#lighting-system) , «Interior Lamp Switch Replacement (Dimmer)»(/cadillac/elr/i-2013-2015/remont/exterior-lights/#lighting-system)
  2. «Control Module References»(/cadillac/elr/i-2013-2015/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM replacement, programming, and setup
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/elr/i-2013-2015/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/elr/i-2013-2015/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/elr/i-2013-2015/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
Turn Signal/Multifunction Switch Headlamps OFF SignalB257A 0011
Turn Signal/Multifunction Switch Headlamps ON SignalB257A 0011
Turn Signal/Multifunction Switch Park Lamps ON Signal2B257A 002
Turn Signal/Multifunction Switch Flash To Pass Signal3806 0011
Turn Signal/Multifunction Switch High Beam SignalB3650 0811
Turn Signal/Multifunction Switch Ground1
1. Headlamps Malfunction 2. Park, License, and/or Tail Lamps Malfunction

For headlamp operation, the body control module (BCM) monitors three signal circuits from the turn signal/multifunction switch. When the turn signal/multifunction switch is in the AUTO position, the three signal circuits are open and the BCM relies on the ambient light sensor input to turn the headlamps and daytime running lamps (DRLs) ON and OFF. When the turn signal/multifunction switch is placed in the OFF position, the turn signal/multifunction switch headlamps OFF signal circuit is grounded, indicating to the BCM that the exterior lamps should be turned OFF. With the turn signal/multifunction switch in the PARK LAMPS position, the turn signal/multifunction switch park lamps ON signal circuit is grounded, indicating that the park lamps have been requested. When the turn signal/multifunction switch is in the HEADLAMP position, both the turn signal/multifunction switch park lamps ON signal circuit and the turn signal/multifunction switch headlamps ON signal circuit are grounded. The BCM responds by commanding the park lamps and headlamps ON.

Battery voltage must be between 9-16 V.

The BCM detects a short to ground in the turn signal/multifunction switch high beam signal circuit.

The high 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 vehicle ON/OFF switch cycles have occurred.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Vehicle OFF, scan tool disconnected, all doors closed, all accessories OFF, disconnect the harness connector at the S78 Turn Signal/Multifunction Switch. It may take up to 2 minutes for all vehicle systems to power down.
  2. Test for less than 15 ohms between the ground circuit terminal 6 and ground. If 15 ohms or greater Vehicle OFF. Test for less than 2 ohms in the ground circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, repair the open/high resistance in the ground connection. If less than 15 ohms
  3. Vehicle in Service Mode.
  4. Verify the scan tool High Beam Select Switch parameter is Inactive. If not Inactive Vehicle OFF, disconnect the X3 harness connector at the K9 Body Control Module. Test for infinite resistance between the signal circuit terminal 11 and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance, replace the K9 Body Control Module. If Inactive
  5. Install a 3 A fused jumper wire between the signal circuit terminal 11 and ground.
  6. Verify the scan tool High Beam Select Switch parameter is Active. If not Active Vehicle OFF, disconnect the X3 harness connector at the K9 Body Control Module, vehicle in Service Mode. Test for less than 1 V between the signal circuit terminal 11 and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V Test for less than 2 ohms in the signal circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K9 Body Control Module. If Active
  7. Test or replace the S78 Turn Signal/Multifunction Switch.

Perform the Diagnostic Repair Verification after completing the repair.

  1. «Turn Signal Switch Replacement»(/cadillac/elr/i-2013-2015/remont/steering-column-switches/#steering-wheel-and-steering-column)
  2. «Control Module References»(/cadillac/elr/i-2013-2015/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM replacement, programming, and setup
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/elr/i-2013-2015/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/elr/i-2013-2015/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/elr/i-2013-2015/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
Turn Signal/Multifunction Switch Headlamps OFF SignalB257A 0011
Turn Signal/Multifunction Switch Headlamps ON SignalB257A 0011
Turn Signal/Multifunction Switch Park Lamps ON Signal2B257A 002
Turn Signal/Multifunction Switch Flash To Pass Signal3806 0011
Turn Signal/Multifunction Switch High Beam SignalB3650 0811
Turn Signal/Multifunction Switch Ground1
1. Headlamps Malfunction 2. Park, License, and/or Tail Lamps Malfunction

When the turn signal/multifunction switch is momentarily placed in the flash to pass position, ground is applied to the body control module (BCM) through the flash to pass signal circuit. The BCM responds to the flash to pass request by applying ground to the 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 high beam fuses to the high beam control circuits illuminating the high beam headlamps. The high beam headlamps will only illuminate for as long at the flash to pass switch is activated.

Battery voltage must be between 9-16 V.

The BCM detects a short to ground in the turn signal/multifunction switch flash to pass signal circuit.

The high beam lamps and the high beam indicator on the instrument panel cluster are always ON.

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

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Vehicle OFF, scan tool disconnected, all doors closed, all accessories OFF, disconnect the harness connector at the S78 Turn Signal/Multifunction Switch. It may take up to 2 minutes for all vehicle systems to power down.
  2. Test for less than 15 ohms between the ground circuit terminal 6 and ground. If 15 ohms or greater Vehicle OFF. Test for less than 2 ohms in the ground circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, repair the open/high resistance in the ground connection. If less than 15 ohms
  3. Vehicle in Service Mode.
  4. Verify the scan tool Headlamps Flash Switch parameter is Inactive. If not Inactive Vehicle OFF, disconnect the X3 harness connector at the K9 Body Control Module. Test for infinite resistance between the signal circuit terminal 12 and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance, replace the K9 Body Control Module. If Inactive
  5. Install a 3 A fused jumper wire between the signal circuit terminal 12 and ground.
  6. Verify the scan tool Headlamps Flash Switch parameter is Active. If not Active Vehicle OFF, disconnect the X3 harness connector at the K9 Body Control Module, vehicle in Service Mode. Test for less than 1 V between the signal circuit terminal 12 and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V Test for less than 2 ohms in the signal circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K9 Body Control Module. If Active
  7. Test or replace the S78 Turn Signal/Multifunction Switch.

Perform the Diagnostic Repair Verification after completing the repair.

  1. «Turn Signal Switch Replacement»(/cadillac/elr/i-2013-2015/remont/steering-column-switches/#steering-wheel-and-steering-column)
  2. «Control Module References»(/cadillac/elr/i-2013-2015/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM replacement, programming, and setup
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/elr/i-2013-2015/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/elr/i-2013-2015/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/elr/i-2013-2015/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
Turn Signal/Multifunction Switch Park Lamps ON Signal1B257A 001
Park Lamps Control - Left RearB3881 02B3881 01, B3881 04B3881 01, B3881 04
Park Lamps Control - Right RearB3882 02B3882 01, B3882 04B3882 01, B3882 04
Tail Lamp Ground - Left1
Tail Lamp Ground - Right1
Turn Signal/Multifunction Switch Ground1
1. Park, License, and/or Tail Lamps Malfunction

When the turn signal/multifunction switch is placed in the HEAD or PARK position, ground is applied to the park lamp switch ON signal circuit to the body control module (BCM). The BCM responds by applying voltage to the park lamps and license lamps control circuits illuminating the park and license lamps.

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

DTC B3881 01 and B3881 04

The BCM detects a short to voltage or an open/high resistance in the left rear park lamp control circuit.

DTC B3881 02

The BCM detects a short to ground in the left rear park lamp control circuit.

DTC B3882 01 and B3882 04

The BCM detects a short to voltage or an open/high resistance in the right rear park lamp control circuit.

DTC B3882 02

The BCM detects a short to ground in the right rear park lamp control circuit.

DTC B3881 01

The left rear park lamp is always ON.

DTC B3881 02 and B3881 04

The left rear park lamp is inoperative.

DTC B3882 01

The right rear park lamp is always ON.

DTC B3882 02 and B3882 04

The right rear park lamp is inoperative.

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

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Vehicle OFF, exterior lamps OFF, trunk latch latched, disconnect the harness connector at the appropriate E42 tail lamp assembly.
  2. Test for less than 5 ohms between the ground circuit terminal 4 and ground. If 5 ohms or greater Vehicle OFF. Test for less than 2 ohms in the ground circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, repair the open/high resistance in the ground connection. If less than 5 ohms
  3. Connect a test lamp between the control circuit terminal 2 and ground, vehicle in Service Mode.
  4. Verify the test lamp turns ON and OFF when commanding the appropriate Rear Park Lamp ON and OFF with a scan tool. If the test lamp is always OFF Vehicle OFF, disconnect the appropriate harness connector listed below at the K9 body control module. X4 - left park lamp X5 - right park lamp Test for infinite resistance between the control circuit and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance Test for less than 2 ohms in the control circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K9 body control module. If the test lamp is always ON Vehicle OFF, disconnect the appropriate harness connector listed below at the K9 body control module, vehicle in Service Mode. X4 - left park lamp X5 - right park lamp Test for less than 1 V between the control circuit terminal and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V, replace the K9 body control module. If the test lamp turns ON and OFF
  5. Test or replace the appropriate E42 tail lamp assembly.

Perform the Diagnostic Repair Verification after completing the repair.

  1. «Tail Lamp Replacement»(/cadillac/elr/i-2013-2015/remont/exterior-lights/#lighting-system)
  2. «Control Module References»(/cadillac/elr/i-2013-2015/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM replacement, programming, and setup
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/elr/i-2013-2015/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/elr/i-2013-2015/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/elr/i-2013-2015/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
License Plate Lamp ControlB3883 02B3883 01, B3883 04B3883 01
License Plate Lamp Ground - Right1
License Plate Lamp Ground - Left1
1. Park, License, and/or Tail Lamps Malfunction

When the turn signal/multifunction switch is placed in the HEAD or PARK position, ground is applied to the park lamp switch ON signal circuit to the body control module (BCM). The BCM responds by applying voltage to the park lamps and license lamps control circuits illuminating the park and license lamps.

DTC B3883 01

Turn signal/multifunction switch in OFF position.

DTC B3883 02 and B3883 04

Turn signal/multifunction switch in AUTO, PARK or ON positions.

DTC B3883 01

The BCM detects a short to voltage in the license plate lamp control circuit.

DTC B3883 02

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

DTC B3883 04

The BCM detects an open/high resistance in the license plate lamp control circuit.

DTC B3883 01

License plate lamps always ON.

DTC B3883 02 and B3883 04

License plate lamps inoperative.

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

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Vehicle OFF, exterior lamps OFF, remove both E7 license plate lamp bulbs.
  2. Test for less than 5 ohms between each ground circuit terminal 2 and ground. If 5 ohms or greater Vehicle OFF. Test for less than 2 ohms in the ground circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, repair the open/high resistance in the ground connection. If less than 5 ohms
  3. Connect a test lamp between the E7L license plate lamp - left control circuit terminal 1 and ground, vehicle in Service Mode.
  4. Verify the test lamp turns ON and OFF when commanding the License Plate Lamps ON and OFF with a scan tool. If the test lamp is always OFF Vehicle OFF, disconnect the X4 harness connector at the K9 body control module. Test for infinite resistance between the control circuit and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance Test for less than 2 ohms in the control circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K9 body control module. If the test lamp is always ON Vehicle OFF, disconnect the X4 harness connector at the K9 body control module, vehicle in Service Mode. Test for less than 1 V between the control circuit terminal and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V, replace the K9 body control module. If the test lamp turns ON and OFF
  5. Vehicle OFF.
  6. Connect a test lamp between the E7R license plate lamp - right control circuit terminal 1 and ground, vehicle in Service Mode.
  7. Verify the test lamp turns ON and OFF when commanding the License Plate Lamps ON and OFF with a scan tool. If the test lamp is always OFF Vehicle OFF, disconnect the X4 harness connector at the K9 body control module. Test for infinite resistance between the control circuit and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance Test for less than 2 ohms in the control circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If the test lamp turns ON and OFF
  8. Test or replace the appropriate E7 license plate lamp bulb.

Perform the Diagnostic Repair Verification after completing the repair.

  1. «Rear License Plate Lamp Replacement»(/cadillac/elr/i-2013-2015/remont/exterior-lights/#lighting-system)
  2. «Control Module References»(/cadillac/elr/i-2013-2015/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM replacement, programming, and setup
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/elr/i-2013-2015/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/elr/i-2013-2015/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/elr/i-2013-2015/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
Center High Mounted Stop Lamp ControlB3884 02B3884 04B3884 01
Center High Mounted Stop Lamp Ground1
1. Stop Lamps Malfunction

The brake pedal position (BPP) sensor is used to sense the action of the driver application of the brake pedal. The BPP 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 BPP sensor. When the variable signal reaches a voltage threshold indicating the brakes have been applied, the BCM will apply battery voltage to the left and right stop lamp control circuits as well as the center high mounted stop lamp (CHMSL) control circuit illuminating the left and right stop lamps and the CHMSL.

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

DTC B3884 01

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

DTC B3884 02

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

DTC B3884 04

The BCM detects an open/high resistance in the CHMSL control circuit.

DTC B3884 01

CHMSL always ON.

DTC B3884 02 and B3884 04

CHMSL inoperative.

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

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Vehicle OFF, exterior lamps OFF, disconnect the harness connector at the E6 center high mounted stop lamp.
  2. Test for less than 5 ohms between the ground circuit terminal 2 and ground. If 5 ohms or greater Vehicle OFF. Test for less than 2 ohms in the ground circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, repair the open/high resistance in the ground connection. If less than 5 ohms
  3. Connect a test lamp between the control circuit terminal 1 and ground, vehicle in Service Mode.
  4. Verify the test lamp turns ON and OFF when commanding the Center Brake Lamp ON and OFF with a scan tool. If the test lamp is always OFF Vehicle OFF, disconnect the X4 harness connector at the K9 body control module. Test for infinite resistance between the control circuit and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance Test for less than 2 ohms in the control circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K9 body control module. If the test lamp is always ON Vehicle OFF, disconnect the X4 harness connector at the K9 body control module, vehicle in Service Mode. Test for less than 1 V between the control circuit terminal and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V, replace the K9 body control module. If the test lamp turns ON and OFF
  5. Test or replace the E6 center high mounted stop lamp.

Perform the Diagnostic Repair Verification after completing the repair.

  1. «High Mount Stop Lamp Replacement»(/cadillac/elr/i-2013-2015/remont/exterior-lights/#lighting-system)
  2. «Control Module References»(/cadillac/elr/i-2013-2015/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM replacement, programming, and setup
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/elr/i-2013-2015/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/elr/i-2013-2015/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/elr/i-2013-2015/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
F6DR (APO/EXT LIGHTS) Fuse B+B3867 01, B3867 04, B3949 01, B3949 04B3867 01, B3867 04, B3949 01, B3949 04
F8DR (TRN SIG/LCKS) Fuse B+B3948 01, B3948 04B3948 01, B3948 04
Stop/Turn Signal Control - Left RearB3950 02B3950 01, B3950 041
Stop/Turn Signal Control - Right RearB3951 02B3951 01, B3951 041
Turn Signal Control - Left FrontB3948 02B3948 01, B3948 041
Turn Signal Control - Right FrontB3949 02B3949 01, B3949 041
Park/Turn Signal Lamp Ground - Left FrontB2585 01, B2585 04, B3948 01, B3948 04
Park/Turn Signal Lamp Ground - Right FrontB3867 01, B3867 04, B3949 01, B3949 04
Tail Lamp Ground - Left1
Tail Lamp Ground - Right1
1. Turn Signal Lamps and/or Indicators Malfunction

Ground is applied at all times to the turn signal/multifunction switch. The turn signal lamps may only be activated with the vehicle ON/OFF switch in the SERVICE MODE or ON positions. 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 responds to the turn signal switch input by applying a pulsating voltage to the front and rear turn signal lamps through there respective control circuits. When a turn signal request is received by the BCM, a serial data message is sent to the instrument panel requesting the respective turn signal indicator be pulsed ON and OFF.

Battery voltage must be between 9-16 V.

DTC B3948 01 and B3948 04

  1. The BCM detects a short to ground or an open/high resistance in the F8DR (TRN SIG/LCKS) fuse B+ circuit.
  2. The BCM detects an open/high resistance in the left front turn signal control circuit.
  3. The BCM detects an open/high resistance in the left front turn signal ground circuit.

DTC B3948 02

The BCM detects a short to ground in the left front turn signal control circuit.

DTC B3949 01 and B3949 04

  1. The BCM detects a short to ground or an open/high resistance in the F6DR (APO/EXT LIGHTS) fuse B+ circuit.
  2. The BCM detects an open/high resistance in the right front turn signal control circuit.
  3. The BCM detects an open/high resistance in the right front turn signal ground circuit.

DTC B3949 02

The BCM detects a short to ground in the right front turn signal control circuit.

DTC B3948

  1. The left front turn signal is inoperative.
  2. The left turn signal indicator on the instrument cluster flashes rapidly.

DTC B3949

  1. The right front turn signal is inoperative.
  2. The right turn signal indicator on the instrument cluster flashes rapidly.
  1. The condition responsible for setting the DTC no longer exists.
  2. A history DTC will clear once 100 consecutive malfunction-free vehicle ON/OFF switch cycles have occurred.

Schematic Reference

  1. «Exterior Lights Schematics»(/cadillac/elr/i-2013-2015/remont/exterior-lights/#lighting-system)
  2. «Body Control System Schematics»(/cadillac/elr/i-2013-2015/remont/communication-devices/#data-communication-system-schematic-wiring-diagrams)

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

DTC B3948

  1. Vehicle OFF, disconnect the X5 harness connector at the K9 Body Control Module, vehicle in Service Mode.
  2. Verify a test lamp illuminates between the B+ circuit terminal 3 and ground. If the test lamp does not illuminate and the circuit fuse is good Vehicle OFF. Test for less than 2 ohms in the B+ circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, verify the fuse is not open and there is voltage at the fuse. If the test lamp does not illuminate and the circuit fuse is open Vehicle OFF. Test for infinite resistance between the B+ circuit and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance, replace the K9 Body Control Module. If the test lamp illuminates
  3. Vehicle OFF, connect the X5 harness connector at the K9 Body Control Module.
  4. Vehicle OFF, exterior lamps OFF, disconnect the harness connectors at the components listed below. E4N turn signal lamp - left E4Y turn signal repeater lamp - left
  5. Test for less than 10 ohms between the ground circuit terminals listed below and ground. E4N turn signal lamp - left terminal 1 E4Y turn signal repeater lamp - left terminal 2 If 10 ohms or greater Vehicle OFF. Test for less than 2 ohms in the ground circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, repair the open/high resistance in the ground connection. If less than 10 ohms
  6. Connect a test lamp between the appropriate control circuit terminal listed below and ground, vehicle in Service Mode. E4N turn signal lamp - left terminal 3 E4Y turn signal repeater lamp - left terminal 1
  7. Verify the test lamp turns ON and OFF when commanding the Left Front Turn Signal Lamp ON and OFF with a scan tool. If the test lamp is always OFF Vehicle OFF, disconnect the X5 harness connector at the K9 Body Control Module. Test for infinite resistance between the control circuit and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance Test for less than 2 ohms in the control circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K9 Body Control Module. If the test lamp is always ON Vehicle OFF, disconnect the X5 harness connector at the K9 Body Control Module, vehicle in Service Mode. Test for less than 1 V between the control circuit terminal and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V, replace the K9 Body Control Module. If the test lamp turns ON and OFF
  8. Test or replace the E4 Turn Signal Lamp - Left.

DTC B3949

  1. Vehicle OFF, disconnect the X2 harness connector at the K9 Body Control Module, vehicle in Service Mode.
  2. Verify a test lamp illuminates between the B+ circuit terminal 3 and ground. If the test lamp does not illuminate and the circuit fuse is good Vehicle OFF. Test for less than 2 ohms in the B+ circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, verify the fuse is not open and there is voltage at the fuse. If the test lamp does not illuminate and the circuit fuse is open Vehicle OFF. Test for infinite resistance between the B+ circuit and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance, replace the K9 Body Control Module. If the test lamp illuminates
  3. Vehicle OFF, connect the X2 harness connector at the K9 Body Control Module.
  4. Vehicle OFF, exterior lamps OFF, disconnect the harness connectors at the components listed below. E4P turn signal lamp - right E4Z turn signal repeater lamp - right
  5. Test for less than 10 ohms between the ground circuit terminals listed below and ground. E4P turn signal lamp - right terminal 1 E4Z turn signal repeater lamp - right terminal 2 If 10 ohms or greater Vehicle OFF. Test for less than 2 ohms in the ground circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, repair the open/high resistance in the ground connection. If less than 10 ohms
  6. Connect a test lamp between the appropriate control circuit terminal listed below and ground, vehicle in Service Mode. E4P turn signal lamp - right terminal 3 E4Z turn signal repeater lamp - right terminal 1
  7. Verify the test lamp turns ON and OFF when commanding the Right Front Turn Signal Lamp ON and OFF with a scan tool. If the test lamp is always OFF Vehicle OFF, disconnect the X4 harness connector at the K9 Body Control Module. Test for infinite resistance between the control circuit and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance Test for less than 2 ohms in the control circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K9 Body Control Module. If the test lamp is always ON Vehicle OFF, disconnect the X4 harness connector at the K9 Body Control Module, vehicle in Service Mode. Test for less than 1 V between the control circuit terminal and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V, replace the K9 Body Control Module. If the test lamp turns ON and OFF
  8. Test or replace the E4 Turn Signal Lamp - Right.

Perform the Diagnostic Repair Verification after completing the repair.

  1. «Outside Rearview Mirror Replacement»(/cadillac/elr/i-2013-2015/remont/mirrors/#mirror-system)
  2. «Control Module References»(/cadillac/elr/i-2013-2015/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM replacement, programming, and setup
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/elr/i-2013-2015/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/elr/i-2013-2015/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/elr/i-2013-2015/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
F6DR (APO/EXT LIGHTS) Fuse B+B3867 01, B3867 04, B3949 01, B3949 04B3867 01, B3867 04, B3949 01, B3949 04
F8DR (TRN SIG/LCKS) Fuse B+B3948 01, B3948 04B3948 01, B3948 04
Stop/Turn Signal Control - Left RearB3950 02B3950 01, B3950 041
Stop/Turn Signal Control - Right RearB3951 02B3951 01, B3951 041
Turn Signal Control - Left FrontB3948 02B3948 01, B3948 041
Turn Signal Control - Right FrontB3949 02B3949 01, B3949 041
Park/Turn Signal Lamp Ground - Left FrontB2585 01, B2585 04, B3948 01, B3948 04
Park/Turn Signal Lamp Ground - Right FrontB3867 01, B3867 04, B3949 01, B3949 04
Tail Lamp Ground - Left1
Tail Lamp Ground - Right1
1. Turn Signal Lamps and/or Indicators Malfunction

Ground is applied at all times to the turn signal/multifunction switch. The turn signal lamps may only be activated with the vehicle ON/OFF switch in the SERVICE MODE or ON positions. 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 responds to the turn signal switch input by applying a pulsating voltage to the front and rear turn signal lamps through there respective control circuits. When a turn signal request is received by the BCM, a serial data message is sent to the instrument panel requesting the respective turn signal indicator be pulsed ON and OFF.

Battery voltage must be between 9-16 V.

DTC B3950 01 and B3950 04

  1. The BCM detects an open/high resistance in the left rear stop/turn signal control circuit.
  2. The BCM detects an open/high resistance in the left rear stop/turn signal ground circuit.

DTC B3950 02

The BCM detects a short to ground in the left rear stop/turn signal control circuit.

DTC B3951 01 and B3951 04

  1. The BCM detects an open/high resistance in the right rear stop/turn signal control circuit.
  2. The BCM detects an open/high resistance in the right rear stop/turn signal ground circuit.

DTC B3951 02

The BCM detects a short to ground in the right rear stop/turn signal control circuit.

DTC B3950

  1. The left rear stop/turn signal is inoperative.
  2. The left turn signal indicator on the instrument cluster flashes rapidly.

DTC B3951

  1. The right rear stop/turn signal is inoperative.
  2. The right turn signal indicator on the instrument cluster flashes rapidly.
  1. The condition responsible for setting the DTC no longer exists.
  2. A history DTC will clear once 100 consecutive malfunction-free vehicle ON/OFF switch cycles have occurred.

Schematic Reference

  1. «Exterior Lights Schematics»(/cadillac/elr/i-2013-2015/remont/exterior-lights/#lighting-system)
  2. «Body Control System Schematics»(/cadillac/elr/i-2013-2015/remont/communication-devices/#data-communication-system-schematic-wiring-diagrams)

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

DTC B3950

  1. Vehicle OFF, exterior lamps OFF, disconnect the harness connector at the E42L tail lamp assembly - left.
  2. Test for less than 5 ohms between the ground circuit terminal 4 and ground. If 5 ohms or greater Vehicle OFF. Test for less than 2 ohms in the ground circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, repair the open/high resistance in the ground connection. If less than 5 ohms
  3. Connect a test lamp between the control circuit terminal 1 and ground, vehicle in Service Mode.
  4. Verify the test lamp turns ON and OFF when commanding the Left Rear Turn Signal/Brake Lamp ON and OFF with a scan tool. If the test lamp is always OFF Vehicle OFF, disconnect the X5 harness connector at the K9 body control module. Test for infinite resistance between the control circuit and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance Test for less than 2 ohms in the control circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K9 body control module. If the test lamp is always ON Vehicle OFF, disconnect the X5 harness connector at the K9 body control module, vehicle in Service Mode. Test for less than 1 V between the control circuit terminal and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V, replace the K9 body control module. If the test lamp turns ON and OFF
  5. Test or replace the E42L tail lamp assembly - left.

DTC B3951

  1. Vehicle OFF, exterior lamps OFF, disconnect the harness connector at the E42R tail lamp assembly - right.
  2. Test for less than 5 ohms between the ground circuit terminal 4 and ground. If 5 ohms or greater Vehicle OFF. Test for less than 2 ohms in the ground circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, repair the open/high resistance in the ground connection. If less than 5 ohms
  3. Connect a test lamp between the control circuit terminal 1 and ground, vehicle in Service Mode.
  4. Verify the test lamp turns ON and OFF when commanding the Right Rear Turn Signal/Brake Lamp ON and OFF with a scan tool. If the test lamp is always OFF Vehicle OFF, disconnect the X4 harness connector at the K9 body control module. Test for infinite resistance between the control circuit and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance Test for less than 2 ohms in the control circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K9 body control module. If the test lamp is always ON Vehicle OFF, disconnect the X4 harness connector at the K9 body control module, vehicle in Service Mode. Test for less than 1 V between the control circuit terminal and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V, replace the K9 body control module. If the test lamp turns ON and OFF
  5. Test or replace the E42R tail lamp assembly - right.

Perform the Diagnostic Repair Verification after completing the repair.

  1. «Tail Lamp Replacement»(/cadillac/elr/i-2013-2015/remont/exterior-lights/#lighting-system)
  2. «Control Module References»(/cadillac/elr/i-2013-2015/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM replacement, programming, and setup
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/elr/i-2013-2015/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/elr/i-2013-2015/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/elr/i-2013-2015/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
F10DL (BCM/EXT LIGHTS) Fuse B+C0890 03, B101E 43, B1395 03, B1517 07, U0121 00, U0128 00, U0422 71C0890 03, B101E 43, B1395 03, B1517 07, U0121 00, U0128 00, U0422 71
Brake Pedal Position Sensor 5 V ReferenceC0277 06, C0890 03, U0422 71, C0561 71C0277 06, U0422 71, C0561 71C0277 07, C0890 07, U0422 71, C0561 71
Brake Pedal Position Sensor SignalC0277 06, U0422 71, C0561 71C0277 06, U0422 71, C0561 71C0277 07, C0890 07, U0422 71, C0561 71C0277 09
Center High Mounted Stop Lamp Control222
Stop/Turn Signal Lamp Control - Left111
Stop/Turn Signal Lamp Control - Right111
Brake Pedal Position Sensor Low ReferenceC0277 06, U0422 71, C0561 711
Center High Mounted Stop Lamp Ground2
Tail/Stop Lamp Ground - Left1
Tail/Stop Lamp Ground - Right1
1. Stop Lamps Malfunction 2. Center High Mounted Stop Lamp Malfunction

The brake pedal position (BPP) sensor is used to sense the action of the driver application of the brake pedal. The BPP 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 BPP sensor. When the variable signal reaches a voltage threshold indicating the brakes have been applied, the BCM will apply battery voltage to the left and right stop lamp control circuits as well as the center high mounted stop lamp (CHMSL) control circuit illuminating the left and right stop lamps and the CHMSL.

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

DTC C0277 06

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

DTC C0277 07

  1. The BCM detects a short to voltage in the BPP sensor 5 V reference circuit.
  2. The BCM detects a short to voltage in the BPP sensor signal circuit.

DTC C0277 09

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

DTC C0277 4B

The DTC will set when the BPP sensor home position is not learned.

DTC C0890 03

  1. The BCM detects a short to ground in the BPP sensor 5 V reference circuit.
  2. The BCM detects a short to ground or an open/high resistance in the F10DL (BCM/EXT LIGHTS) fuse B+ circuit.

DTC C0890 07

  1. The BCM detects a short to voltage in the BPP sensor 5 V reference circuit.
  2. The BCM detects a short to voltage in the BPP sensor low reference circuit.

DTC C0277 06 and C0890 03

  1. The vehicle will not start with a short to ground or an open/high resistance on the BPPS 5 V reference circuit or the BPPS signal circuit.
  2. The vehicle will start with an open/high resistance on the BPPS low reference circuit without applying the brake pedal.

DTC C0277 07 and C0890 07

The vehicle will not start with a short to voltage on the BPPS 5 V reference circuit or the BPPS signal circuit.

  1. The condition responsible for setting the DTC no longer exists.
  2. For DTC C0277 4B a successful brake pedal position sensor calibration has been performed.
  3. A history DTC will clear once 50 consecutive malfunction-free vehicle ON/OFF switch cycles have occurred.
  4. A DTC will not clear the current status until the next ignition cycle.

Schematic Reference

  1. «Exterior Lights Schematics»(/cadillac/elr/i-2013-2015/remont/exterior-lights/#lighting-system)
  2. «Body Control System Schematics»(/cadillac/elr/i-2013-2015/remont/communication-devices/#data-communication-system-schematic-wiring-diagrams)

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

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

  1. Vehicle OFF, disconnect the harness connector at the B22 brake pedal position sensor, vehicle in Service Mode.
  2. Verify a test lamp illuminates between the low reference circuit terminal C and B+. If the test lamp does not illuminate Vehicle OFF, disconnect the X1 harness connector at the K9 body control module. Test for less than 2 ohms in the low reference circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K9 body control module. If the test lamp illuminates
  3. Vehicle in Service Mode.
  4. Test for 4.8-5.2 V between the 5 V reference circuit terminal A and ground. If less than 4.8 V Vehicle OFF, disconnect the X2 harness connector at the K9 body control module. Test for infinite resistance between the 5 V reference circuit and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance Test for less than 2 ohms in the 5 V reference circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K9 body control module. If greater than 5.2 V Vehicle OFF, disconnect the X2 harness connector at the K9 body control module, vehicle in Service Mode. Test for less than 1 V between the 5 V reference circuit and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V, replace the K9 body control module. If between 4.8-5.2 V
  5. Verify the scan tool Brake Pedal Applied parameter is Inactive. If not Inactive Vehicle OFF, disconnect the X2 harness connector at the K9 body control module, vehicle in Service Mode. Test for less than 1 V between the signal circuit terminal B and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V, replace the K9 body control module. If Inactive
  6. Install a 3 A fused jumper wire between the 5-volt reference circuit terminal A and the signal circuit terminal B.
  7. Verify the scan tool Brake Pedal Applied parameter is Active. If not Active Vehicle OFF, disconnect the X2 harness connector at the K9 body control module. Test for infinite resistance between the signal circuit and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance Test for less than 2 ohms in the signal circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K9 body control module. If Active
  8. Test or replace the B22 brake pedal position sensor.

DTC C0277 4B

  1. Verify DTC C0277 4B is not set. If DTC C0277 4B is set Vehicle in Service Mode. Perform the BPP sensor recalibration procedure for the K9 body control module. Refer to «Brake Pedal Position Sensor Calibration»(/cadillac/elr/i-2013-2015/remont/exterior-lights/#lighting-system__brake-pedal-position-sensor-calibration) . Verify the DTC does not reset while operating the vehicle under the conditions for running the DTC. If the DTC resets, replace the B22 brake pedal position sensor. If the DTC does not reset All OK. If DTC C0277 4B is not set
  2. All OK.

DTC C0277 09

  1. Verify DTC C0277 09 is not set. If DTC C0277 09 is set Replace the B22 brake pedal position sensor. Perform the BPP sensor recalibration procedure for the K9 body control module. Refer to «Brake Pedal Position Sensor Calibration»(/cadillac/elr/i-2013-2015/remont/exterior-lights/#lighting-system__brake-pedal-position-sensor-calibration) . Verify the DTC does not reset while operating the vehicle under the conditions for running the DTC. If the DTC resets, replace the K9 body control module. If the DTC does not reset All OK. If DTC C0277 09 is not set
  2. All OK.

Perform the Diagnostic Repair Verification after completing the repair.

  1. «Brake Pedal Position Sensor Calibration»(/cadillac/elr/i-2013-2015/remont/exterior-lights/#lighting-system__brake-pedal-position-sensor-calibration)
  2. «Brake Pedal Position Sensor Replacement»(/cadillac/elr/i-2013-2015/remont/exterior-lights/#lighting-system__brake-pedal-position-sensor-replacement)
  3. «Control Module References»(/cadillac/elr/i-2013-2015/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM replacement, programming, and setup
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/elr/i-2013-2015/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/elr/i-2013-2015/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/elr/i-2013-2015/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
Brake Applied SignalC0297 02C0297 021
1. 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, engine control module (ECM), and center high mounted stop lamp control circuit.

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

The BCM detects a short to ground or an open/high resistance on the brake applied signal circuit.

The cruise control system is disabled.

  1. The condition responsible for setting the DTC no longer exists.
  2. A history DTC will clear once 50 consecutive malfunction-free vehicle ON/OFF switch cycles have occurred.

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/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Vehicle OFF, disconnect the X1 harness connector at the K20 engine control module.
  2. Connect a test lamp between the signal circuit terminal 33 and ground, vehicle in Service Mode.
  3. Verify the test lamp turns ON and OFF while pressing and releasing the brake pedal. If the test lamp is always OFF Vehicle OFF, disconnect the X5 harness connector at the K9 body control module. Test for infinite resistance between the signal circuit and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance Test for less than 2 ohms in the signal circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K9 body control module. If the test lamp is always ON Vehicle OFF, disconnect the X5 harness connector at the K9 body control module, vehicle in Service Mode. Test for less than 1 V between the signal circuit terminal and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V, replace the K9 body control module. If the test lamp turns ON and OFF
  4. Replace the K20 engine control module.

Perform the Diagnostic Repair Verification after completing the repair.

  1. «Brake Pedal Position Sensor Calibration»(/cadillac/elr/i-2013-2015/remont/exterior-lights/#lighting-system__brake-pedal-position-sensor-calibration)
  2. «Control Module References»(/cadillac/elr/i-2013-2015/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM or ECM replacement, programming, and setup

Symptoms - Lighting

Note. The following steps must be completed before using a symptom table.

  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/elr/i-2013-2015/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) 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.
  2. 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»(/cadillac/elr/i-2013-2015/remont/exterior-lights/#lighting-system) «Interior Lighting Systems Description and Operation»(/cadillac/elr/i-2013-2015/remont/exterior-lights/#lighting-system)

Visual/Physical Inspection

  1. Inspect for aftermarket devices which could affect the operation of the lighting system. Refer to «Checking Aftermarket Accessories»(/cadillac/elr/i-2013-2015/remont/body-electrical/#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. «Backup Lamps Malfunction»(/cadillac/elr/i-2013-2015/remont/exterior-lights/#lighting-system)
  2. «Courtesy Lamps Malfunction»(/cadillac/elr/i-2013-2015/remont/exterior-lights/#lighting-system)
  3. «Daytime Running Lamps Malfunction»(/cadillac/elr/i-2013-2015/remont/exterior-lights/#lighting-system)
  4. «Dome Lamps Malfunction»(/cadillac/elr/i-2013-2015/remont/exterior-lights/#lighting-system)
  5. «Hazard Lamps Malfunction»(/cadillac/elr/i-2013-2015/remont/exterior-lights/#lighting-system)
  6. «Headlamps Malfunction»(/cadillac/elr/i-2013-2015/remont/exterior-lights/#lighting-system)
  7. «Interior Backlighting Malfunction»(/cadillac/elr/i-2013-2015/remont/exterior-lights/#lighting-system)
  8. «Park, License, and/or Tail Lamps Malfunction»(/cadillac/elr/i-2013-2015/remont/exterior-lights/#lighting-system)
  9. «Rear Compartment Lamp Malfunction»(/cadillac/elr/i-2013-2015/remont/exterior-lights/#lighting-system)
  10. «Stop Lamps Malfunction»(/cadillac/elr/i-2013-2015/remont/exterior-lights/#lighting-system)
  11. «Turn Signal Lamps and/or Indicators Malfunction»(/cadillac/elr/i-2013-2015/remont/exterior-lights/#lighting-system)
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/elr/i-2013-2015/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/elr/i-2013-2015/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/elr/i-2013-2015/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
F7DR (INT LAMPS) Fuse B+B2545 01, B2545 04, B2615 02B2545 01, B2545 04, B2615 02
Backup Lamp ControlB2545 02B2545 01, B2545 041
Backup Lamp Ground1
1. Backup Lamps Malfunction

With the vehicle ON and the transmission 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 lamp control circuit illuminating the backup lamp. 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 vehicle must be ON for the backup lamps to operate.

Schematic Reference

  1. «Exterior Lights Schematics»(/cadillac/elr/i-2013-2015/remont/exterior-lights/#lighting-system)
  2. «Body Control System Schematics»(/cadillac/elr/i-2013-2015/remont/communication-devices/#data-communication-system-schematic-wiring-diagrams)

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Vehicle OFF, disconnect the X5 harness connector at the K9 body control module, vehicle in Service Mode.
  2. Verify a test lamp illuminates between the B+ circuit terminal 4 and ground. If the test lamp does not illuminate and the circuit fuse is good Vehicle OFF. Test for less than 2 ohms in the B+ circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, verify the fuse is not open and there is voltage at the fuse. If the test lamp does not illuminate and the circuit fuse is open Vehicle OFF. Test for infinite resistance between the B+ circuit and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance, replace the K9 body control module. If the test lamp illuminates
  3. Vehicle OFF, connect the X5 harness connector at the K9 body control module.
  4. Vehicle OFF, exterior lamps OFF, disconnect the harness connector at the E5 backup lamp.
  5. Test for less than 5 ohms between the ground circuit terminal and ground. If 5 ohms or greater Vehicle OFF. Test for less than 2 ohms in the ground circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, repair the open/high resistance in the ground connection. If less than 5 ohms
  6. Connect a test lamp between the control circuit terminal and ground, vehicle in Service Mode.
  7. Verify the test lamp turns ON and OFF when commanding the Backup Lamps ON and OFF with a scan tool. If the test lamp is always OFF Vehicle OFF, disconnect the X7 harness connector at the K9 body control module. Test for infinite resistance between the control circuit and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance Test for less than 2 ohms in the control circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K9 body control module. If the test lamp is always ON Vehicle OFF, disconnect the X7 harness connector at the K9 body control module, vehicle in Service Mode. Test for less than 1 V between the control circuit terminal and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V, replace the K9 body control module. If the test lamp turns ON and OFF
  8. Test or replace the E5 backup lamp.

Perform the Diagnostic Repair Verification after completing the repair.

  1. «Backup Lamp Bulb Replacement»(/cadillac/elr/i-2013-2015/remont/exterior-lights/#lighting-system)
  2. «Control Module References»(/cadillac/elr/i-2013-2015/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM replacement, programming, and setup
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/elr/i-2013-2015/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/elr/i-2013-2015/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/elr/i-2013-2015/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
F7DR (INT LAMPS) Fuse B+B2545 01, B2545 04, B2615 02B2545 01, B2545 04, B2615 02
Courtesy Lamps Control - Terminal 2 X7B1480 0211
Dome Lamps ControlB2545 01, B2545 04, B2615 0222
Dome Lamp Ground2
Dome/Reading Lamps - Front Ground1, 2
Sunshade Mirror Lamp - Left Ground1
Sunshade Mirror Lamp - Right Ground1
1. Courtesy Lamps Malfunction 2. Dome Lamps Malfunction

The body control module (BCM) supplies battery voltage to the front reading lamps and left and right sunshade lamps via the courtesy lamp control circuit. When a sunshade mirror is opened, the switch contact close allowing battery voltage to flow illuminating the respective lamps. The front reading lamps are controlled by individual switches that are activated by the operator when additional cabin lighting is required. In the event that any of these courtesy lamps were to remain illuminated for more than 10 minutes with the vehicle ON/OFF switch in the OFF position and no doors opened, the BCM will deactivate the courtesy lamp control circuit to prevent total battery discharge.

When the F7DR (INT LAMPS) fuse is open, both dome lamps, sunshade lamps, reading lamps, and backup lamps will be inoperative. DTC B2545 will also set for the backup lamps when the vehicle is placed in the reverse gear.

Schematic Reference

  1. «Interior Lights Dimming Schematics»(/cadillac/elr/i-2013-2015/remont/exterior-lights/#lighting-system)
  2. «Body Control System Schematics»(/cadillac/elr/i-2013-2015/remont/communication-devices/#data-communication-system-schematic-wiring-diagrams)

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Vehicle OFF, scan tool disconnected, all doors closed, all accessories OFF, disconnect the harness connectors at the components listed below. It may take up to 2 minutes for all vehicle systems to power down. E37F dome/reading lamps - front E31L sunshade mirror lamp - left E31R sunshade mirror lamp - right
  2. Test for less than 10 ohms between the appropriate ground circuit terminal listed below and ground. E37F dome/reading lamps - front - terminal 6 A31L sunshade - left - terminal B A31R sunshade - right - terminal B If 10 ohms or greater Vehicle OFF. Test for less than 2 ohms in the ground circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, repair the open/high resistance in the ground connection. If less than 10 ohms
  3. Connect a test lamp between the appropriate control circuit terminal listed below and ground, vehicle in Service Mode. E37F dome/reading lamps - front terminal 1 E31L sunshade mirror lamp - left terminal A E31R sunshade mirror lamp - right terminal A
  4. Verify the test lamp turns ON and OFF when commanding the Inadvertent Load ON and OFF with a scan tool. If the test lamp is always OFF Vehicle OFF, disconnect the X7 harness connector at the K9 body control module. Test for infinite resistance between the control circuit and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance Test for less than 2 ohms in the control circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K9 body control module. If the test lamp is always ON Vehicle OFF, disconnect the X7 harness connector at the K9 body control module, vehicle in Service Mode. Test for less than 1 V between the control circuit terminal and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V, replace the K9 body control module. If the test lamp turns ON and OFF
  5. Test or replace the appropriate courtesy lamp.

Perform the Diagnostic Repair Verification after completing the repair.

  1. «Sunshade Replacement»(/cadillac/elr/i-2013-2015/remont/exteriorinterior-trim/#interior-trim-and-interior-paneling)
  2. «Center Reading and Courtesy Lamp Replacement»(/cadillac/elr/i-2013-2015/remont/exterior-lights/#lighting-system)
  3. «Control Module References»(/cadillac/elr/i-2013-2015/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM replacement, programming, and setup
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/elr/i-2013-2015/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/elr/i-2013-2015/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/elr/i-2013-2015/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
Ambient Light Sensor Low Reference1B2645 07, B0163 05, B0183 051
Daytime Running Lamp Control - LeftB2600 0211
Daytime Running Lamp Control - RightB2605 0211
Daytime Running Lamp Ground - Left1
Daytime Running Lamp Ground - Right1
1. 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 volts depending on outside lighting conditions. The body control module (BCM) provides a 5-volt reference signal to the ambient light sensor and the HVAC control module provides a low reference ground. The BCM monitors the ambient light sensor signal circuit to determine if outside lighting conditions are correct for either daytime running lights (DRL) or the automatic headlamp system when the headlamp switch is in the AUTO position. In daylight conditions, the BCM will command the DRLs ON by applying voltage to the left and right DRL control circuits illuminating the DRLs. Any function or condition that turns on the headlamps will cancel DRL operation.

The daytime running lamps will only operate in daylight conditions with the vehicle ON and in any transmission gear except PARK.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

  1. Vehicle ON.
  2. Verify the left daytime running lamps turn ON and OFF when commanding the Left Dedicated Daytime Running Lamp ON and OFF with a scan tool. If the left daytime running lamps do not turn ON and OFF Refer to Daytime Running Lamps Malfunction. If the left daytime running lamps turn ON and OFF
  3. Verify the right daytime running lamps turns ON and OFF when commanding the Right Dedicated Daytime Running Lamp ON and OFF with a scan tool. If the right daytime running lamps do not turn ON and OFF Refer to Daytime Running Lamps Malfunction. If the right daytime running lamps turn ON and OFF
  4. Refer to Ambient Light Sensor Malfunction.

Ambient Light Sensor Malfunction

  1. Vehicle OFF, scan tool disconnected, all doors closed, all accessories OFF, open and close drivers door, disconnect the harness connector at the B10B Ambient Light/Sunload Sensor. It may take up to 2 minutes for all vehicle systems to power down.
  2. Test for less than 15 ohms between the low reference circuit terminal 6 and ground. If 15 ohms or greater Vehicle OFF, disconnect the X1 harness connector at the K33 HVAC Control Module, vehicle in Service Mode. Test for less than 1 V between the low reference circuit terminal 6 and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V Test for less than 2 ohms in the low reference circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K33 HVAC Control Module. If less than 15 ohms
  3. Vehicle in Service Mode.
  4. Verify the scan tool Ambient Light Sensor parameter is greater than 4.65 V. If 4.65 V or less Vehicle OFF, disconnect the X2 harness connector at the K9 Body Control Module. Test for infinite resistance between the signal circuit terminal 5 and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance, replace the K9 Body Control Module. If greater than 4.65 V
  5. Install a 3 A fused jumper wire between the signal circuit terminal 5 and the low reference circuit terminal 6.
  6. Verify the scan tool Ambient Light Sensor parameter is less than 0.196 V. If 0.196 V or greater Vehicle OFF, disconnect the X2 harness connector at the K9 Body Control Module, vehicle in Service Mode. Test for less than 1 V between the signal circuit terminal 5 and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V Test for less than 2 ohms in the signal circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K9 Body Control Module. If less than 0.196 V
  7. Test or replace the B10 Ambient Light Sensor.

Daytime Running Lamps Malfunction - Upper

  1. Vehicle OFF, exterior lamps OFF, disconnect the harness connector at the inoperative E13 headlamp.
  2. Test for less than 5 ohms between the ground circuit terminal 3 and ground. If 5 ohms or greater Vehicle OFF. Test for less than 2 ohms in the ground circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, repair the open/high resistance in the ground connection. If less than 5 ohms
  3. Connect a test lamp between the control circuit terminal 4 and ground, vehicle ON.
  4. Verify the test lamp turns ON and OFF when commanding the appropriate Dedicated Daytime Running Lamp ON and OFF with a scan tool. If the test lamp is always OFF Vehicle OFF, disconnect the appropriate harness connector listed below at the K9 Body Control Module. X4 - left daytime running lamp X5 - right daytime running lamp Test for infinite resistance between the control circuit and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance Test for less than 2 ohms in the control circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K9 Body Control Module. If the test lamp is always ON Vehicle OFF, disconnect the appropriate harness connector listed below at the K9 Body Control Module, vehicle ON. X4 - left daytime running lamp X5 - right daytime running lamp Test for less than 1 V between the control circuit terminal and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V, replace the K9 Body Control Module. If the test lamp turns ON and OFF
  5. Test or replace the E4 Daytime Running Lamp.

Daytime Running Lamps Malfunction - Lower

  1. Vehicle OFF, exterior lamps OFF, disconnect the harness connector at the inoperative E4 Park/Daytime Running Lamp - Lower.
  2. Test for less than 5 ohms between the ground circuit terminal C and ground. If 5 ohms or greater Vehicle OFF. Test for less than 2 ohms in the ground circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, repair the open/high resistance in the ground connection. If less than 5 ohms
  3. Connect a test lamp between the control circuit terminal B and ground, vehicle ON.
  4. Verify the test lamp turns ON and OFF when commanding the appropriate Park/Daytime Running Lamp ON and OFF with a scan tool. If the test lamp is always OFF Vehicle OFF, disconnect the appropriate harness connector listed below at the K9 Body Control Module. X4 - left daytime running lamp X7 - right daytime running lamp Test for infinite resistance between the control circuit and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance Test for less than 2 ohms in the control circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K9 Body Control Module. If the test lamp is always ON Vehicle OFF, disconnect the appropriate harness connector listed below at the K9 Body Control Module, vehicle ON. X4 - left daytime running lamp X7 - right daytime running lamp Test for less than 1 V between the control circuit terminal and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V, replace the K9 Body Control Module. If the test lamp turns ON and OFF
  5. Test or replace the E4 Park/Daytime Running Lamp - Lower.

Perform the Diagnostic Repair Verification after completing the repair.

  1. «Headlamp Replacement»(/cadillac/elr/i-2013-2015/remont/exterior-lights/#lighting-system)
  2. «Sun Load Temperature and Headlamp Automatic Control Ambient Light Sensor Replacement»(/cadillac/elr/i-2013-2015/remont/automatic-hvac-system/#hvac-system-automatic)
  3. «Control Module References»(/cadillac/elr/i-2013-2015/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM or HVAC control module replacement, programming, and setup
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/elr/i-2013-2015/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/elr/i-2013-2015/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/elr/i-2013-2015/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
F7DR (INT LAMPS) Fuse B+B2545 01, B2545 04, B3950 01, B3950 04B2545 01, B2545 04, B3950 01, B3950 04
Dome Lamps ControlB2545 01, B2545 04, B3950 01, B3950 0411
Dome Lamp Switch Cancel Signal222
Dome Lamp Switch ON Signal222
Dome Lamp Ground - Front1, 2
Dome Lamp Ground - Middle1
1. Dome Lamps Malfunction 2. Dome Lamp Switch Malfunction

The dome lamp switch has 3 positions: DOOR, OFF, and ON. The ON position provides a ground for continuous operation and the dome lamps will remain illuminated until the switch is placed in either the DOOR or OFF position. When in the DOOR position, the dome lamps operation is controlled by the body control module (BCM). When any door is opened, the door ajar switch contacts close and the BCM receives a door-open input. The BCM illuminates the dome lamps when any door is opened or a door lock/unlock request is activated with the key fob. After all doors have been closed, the dome lamps will remain illuminated approximately 3 seconds after the last door closes. When the driver places the dome lamp switch in the OFF position, the dome lamps will be disabled. In the event that the dome lamps were to remain illuminated for more than 10 minutes with the vehicle ON/OFF switch in the OFF position and no doors opened, the BCM will deactivate the dome lamps control circuit to prevent total battery discharge.

Schematic Reference

  1. «Interior Lights Schematics»(/cadillac/elr/i-2013-2015/remont/exterior-lights/#lighting-system)
  2. «Body Control System Schematics»(/cadillac/elr/i-2013-2015/remont/communication-devices/#data-communication-system-schematic-wiring-diagrams)

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Vehicle in Service Mode.
  2. Verify the scan tool Door Ajar Sw. parameter changes between Active and Inactive while opening and closing each vehicle door. If the parameter does not change Refer to «Door Ajar Indicator Malfunction»(/cadillac/elr/i-2013-2015/remont/door-locks-anti-theft-systems/#power-door-lock-system-and-release-systems) . If the parameter changes
  3. Verify the scan tool Interior/Courtesy Lighting Master Switch parameter changes between Door, On, and Cancel while placing the dome lamp switch in the Door, On, and Cancel positions. If the parameter does not change Refer to Dome Lamp Switch Malfunction. If the parameter changes
  4. Verify the dome lamps turn ON and OFF while commanding the Courtesy Lamps ON and OFF with a scan tool. If the dome lamps do not turn ON and OFF Refer to Dome Lamp Malfunction. If the dome lamps turn ON and OFF
  5. All OK.

Dome Lamp Switch Malfunction

  1. Vehicle OFF, scan tool disconnected, all doors closed, all accessories OFF, disconnect the harness connector at the E37F dome/reading lamps - front. It may take up to 2 minutes for all vehicle systems to power down.
  2. Test for less than 5 ohms between the ground circuit terminal 6 and ground. If 5 ohms or greater Vehicle OFF. Test for less than 2 ohms in the ground circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, repair the open/high resistance in the ground connection. If less than 5 ohms
  3. Vehicle in Service Mode.
  4. Verify the scan tool Interior/Courtesy Lighting Master Switch parameter is Door. If Cancel Vehicle OFF, disconnect the X1 harness connector at the K9 body control module. Test for infinite resistance between the signal circuit terminal 4 and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance, replace the K9 body control module. If On Vehicle OFF, disconnect the X7 harness connector at the K9 body control module. Test for infinite resistance between the signal circuit terminal 5 and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance, replace the K9 body control module. If Door
  5. Install a 3 A fused jumper wire between the signal circuit terminal 4 and the ground circuit terminal 6.
  6. Verify the scan tool Interior/Courtesy Lighting Master Switch parameter is Cancel. If not Cancel Vehicle OFF, disconnect the X1 harness connector at the K9 body control module, vehicle in Service Mode. Test for less than 1 V between the signal circuit terminal 4 and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V Test for less than 2 ohms in the signal circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K9 body control module. If Cancel
  7. Install a 3 A fused jumper wire between the signal circuit terminal 5 and the ground circuit terminal 6.
  8. Verify the scan tool Interior/Courtesy Lighting Master Switch parameter is On. If not On Vehicle OFF, disconnect the X7 harness connector at the K9 body control module, vehicle in Service Mode. Test for less than 1 V between the signal circuit terminal 5 and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V Test for less than 2 ohms in the signal circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K9 body control module. If On
  9. Test or replace the E37F dome/reading lamps - front.

Dome Lamps Malfunction

  1. Vehicle OFF, scan tool disconnected, all doors closed, all accessories OFF, disconnect the harness connector at the E37F dome/reading lamps - front and E36AH dome lamp - middle. It may take up to 2 minutes for all vehicle systems to power down.
  2. Test for less than 10 ohms between the ground circuit terminals listed below and ground. E37F dome reading lamps - front terminal 6 E36AH dome lamp - middle terminal 6 If 10 ohms or greater Vehicle OFF. Test for less than 2 ohms in the ground circuits end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, repair the open/high resistance in the ground connection. If less than 10 ohms
  3. Connect a test lamp between the control circuit terminals listed below and ground. E37F dome reading lamps - front terminal 2 E36AH dome lamp - middle terminal 2
  4. Verify the test lamp turns ON and OFF when commanding the Courtesy Lamps ON and OFF with a scan tool. If the test lamp is always OFF Vehicle OFF, disconnect the X7 harness connector at the K9 body control module. Test for infinite resistance between the control circuit and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance Test for less than 2 ohms in the control circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K9 body control module. If the test lamp is always ON Vehicle OFF, disconnect the X7 harness connector at the K9 body control module, vehicle in Service Mode. Test for less than 1 V between the control circuit terminal and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V, replace the K9 body control module. If the test lamp turns ON and OFF
  5. Test or replace the inoperative dome/reading lamp.

Perform the Diagnostic Repair Verification after completing the repair.

  1. «Dome and Reading Lamp Switch Replacement»(/cadillac/elr/i-2013-2015/remont/exterior-lights/#lighting-system)
  2. «Center Reading Lamp Replacement»(/cadillac/elr/i-2013-2015/remont/exterior-lights/#lighting-system)
  3. «Center Reading and Courtesy Lamp Replacement»(/cadillac/elr/i-2013-2015/remont/exterior-lights/#lighting-system)
  4. «Control Module References»(/cadillac/elr/i-2013-2015/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM replacement, programming, and setup
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/elr/i-2013-2015/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/elr/i-2013-2015/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/elr/i-2013-2015/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 0022
Rear Fog Lamps ControlB2540 02B2540 041
Rear Fog Lamp Ground1
Turn Signal/Multifunction Switch Ground2
1. Rear Fog Lamp Malfunction 2. Rear Fog Lamp Switch Malfunction

The rear fog lamp switch signal circuit is grounded momentarily by pressing the rear fog lamp switch. The body control module (BCM) responds to the rear fog lamp request by applying voltage to the rear fog lamp control circuit which illuminates the rear fog lamp.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Vehicle in Service Mode, headlamps ON.
  2. Verify the scan tool Rear Fog Lamps Switch parameter changes between Active and Inactive while commanding the rear fog lamp ON and OFF with the rear fog lamp switch. If the parameter does not change Refer to Rear Fog Lamp Switch Malfunction. If the parameter changes
  3. Verify the rear fog lamp turns ON and OFF when commanding the Rear Fog Lamps ON and OFF with a scan tool. If the rear fog lamp does not turn ON and OFF Refer to Rear Fog Lamp Malfunction. If the rear fog lamp turns ON and OFF
  4. Verify the rear fog lamp indicator on the instrument cluster turns ON and OFF while commanding the rear fog lamp ON and OFF with the rear fog lamp switch. If the rear fog lamp indicator does not turn ON and OFF Refer to Rear Fog Lamp Indicator Malfunction. If the rear fog lamp indicator turns ON and OFF
  5. All OK.

Rear Fog Lamp Switch Malfunction

  1. Vehicle OFF, scan tool disconnected, all doors closed, all accessories OFF, disconnect the harness connector at the S78 Turn Signal/Multifunction Switch. It may take up to 2 minutes for all vehicle systems to power down.
  2. Test for less than 15 ohms between the ground circuit terminal 6 and ground. If 15 ohms or greater Vehicle OFF. Test for less than 2 ohms in the ground circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, repair the open/high resistance in the ground connection. If less than 15 ohms
  3. Vehicle in Service Mode.
  4. Verify the scan tool Rear Fog Lamp Switch parameter is Inactive. If not Inactive Vehicle OFF, disconnect the X1 harness connector at the K9 Body Control Module. Test for infinite resistance between the signal circuit terminal 1 and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance, replace the K9 Body Control Module. If Inactive
  5. Install a 3 A fused jumper wire between the signal circuit terminal 1 and ground.
  6. Verify the scan tool Rear Fog Lamp Switch parameter is Active. If not Active Vehicle OFF, disconnect the X1 harness connector at the K9 Body Control Module, vehicle in Service Mode. Test for less than 1 V between the signal circuit terminal 1 and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V Test for less than 2 ohms in the signal circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K9 Body Control Module. If Active
  7. Test or replace the S78 Turn Signal/Multifunction Switch.

Rear Fog Lamp Malfunction

  1. Vehicle OFF, exterior lamps OFF, disconnect the harness connector at the E29R Fog Lamp - Rear.
  2. Test for less than 5 ohms between the ground circuit terminal 2 and ground. If 5 ohms or greater Vehicle OFF. Test for less than 2 ohms in the ground circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, repair the open/high resistance in the ground connection. If less than 5 ohms
  3. Connect a test lamp between the control circuit terminal 3 and ground, vehicle in Service Mode.
  4. Verify the test lamp turns ON and OFF when commanding the Rear Fog Lamp ON and OFF with a scan tool. If the test lamp is always OFF Vehicle OFF, disconnect the X6 harness connector at the K9 Body Control Module. Test for infinite resistance between the control circuit and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance Test for less than 2 ohms in the control circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K9 Body Control Module. If the test lamp is always ON Vehicle OFF, disconnect the X6 harness connector at the K9 Body Control Module, vehicle in Service Mode. Test for less than 1 V between the control circuit terminal and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V, replace the K9 Body Control Module. If the test lamp turns ON and OFF
  5. Test or replace the E29R Fog Lamp - Rear.

Rear Fog Lamp Indicator Malfunction

  1. Vehicle in Service Mode.
  2. Verify the rear fog lamp indicator turns ON and OFF when commanding the Instrument Cluster All Indicators Test ON and OFF with a scan tool. If the rear fog lamp indicator is always OFF or remains ON Replace the P16 Instrument Cluster. If the rear fog lamp indicator turns ON and OFF
  3. Replace the K9 Body Control Module.

Perform the Diagnostic Repair Verification after completing the repair.

  1. «Turn Signal Switch Replacement»(/cadillac/elr/i-2013-2015/remont/steering-column-switches/#steering-wheel-and-steering-column)
  2. «Control Module References»(/cadillac/elr/i-2013-2015/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM and instrument cluster replacement, programming, and setup
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/elr/i-2013-2015/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/elr/i-2013-2015/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/elr/i-2013-2015/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 Warning Switch Signal111B3596 00
Hazard Warning Switch Ground1
1. Hazard Lamps Malfunction

The hazard flashers may be activated in any power mode. The hazard warning switch signal circuit is momentarily grounded when the hazard warning switch is pressed. The body control module (BCM) responds to the hazard warning switch signal input by supplying battery voltage to all four turn signal lamps in an ON and OFF duty cycle. When the hazard warning switch is activated, the BCM sends a serial data message to the instrument cluster 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/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Vehicle in Service Mode.
  2. Verify the scan tool Hazard Lamps Switch parameter changes between Active and Inactive while commanding the hazard lamps ON and OFF with the hazard warning switch. If the parameter does not change Refer to Circuit/System Testing. If the parameter changes
  3. Verify all left and right turn signal lamps turn ON and OFF while commanding the hazard lamps ON and OFF with the hazard warning switch. If all turn signal lamps do not turn ON and OFF Refer to «Turn Signal Lamps and/or Indicators Malfunction»(/cadillac/elr/i-2013-2015/remont/exterior-lights/#lighting-system) If all turn signal lamps turn ON and OFF
  4. All OK.
  1. Vehicle OFF, scan tool disconnected, all doors closed, all accessories OFF, disconnect the harness connector at the A20 radio/HVAC controls. It may take up to 2 minutes for all vehicle systems to power down.
  2. Test for less than 5 ohms between the ground circuit terminal 17 and ground. If 5 ohms or greater Vehicle OFF. Test for less than 2 ohms in the ground circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, repair the open/high resistance in the ground connection. If less than 5 ohms
  3. Vehicle in Service Mode.
  4. Verify the scan tool Hazard Lamps Switch parameter is Inactive. If not Inactive Vehicle OFF, disconnect the X2 harness connector at the K9 body control module. Test for infinite resistance between the signal circuit terminal 16 and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance, replace the K9 body control module. If Inactive
  5. Install a 3 A fused jumper wire between the signal circuit terminal 16 and the ground terminal 17.
  6. Verify the scan tool Hazard Lamps Switch parameter is Active. If not Active Vehicle OFF, disconnect the X2 harness connector at the K9 body control module, vehicle in Service Mode. Test for less than 1 V between the signal circuit terminal 1 and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V Test for less than 2 ohms in the signal circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K9 body control module. If Active
  7. Test or replace the A20 radio/HVAC controls.

Perform the Diagnostic Repair Verification after completing the repair.

  1. «Radio Control Assembly Replacement»(/cadillac/elr/i-2013-2015/remont/entertainment-systems/#cellular-system-entertainment-system-and-navigation-system)
  2. «Control Module References»(/cadillac/elr/i-2013-2015/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM replacement, programming, and setup
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/elr/i-2013-2015/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/elr/i-2013-2015/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/elr/i-2013-2015/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
F4DR (RT HDLP) Fuse B+11
F11DL (LT HDLP) Fuse B+11
Headlamp High Beam Relay ControlB2580 02, B2580 04B2580 02, B2580 04B2580 01
Low Beam Headlamp Control - Left111
Low Beam Headlamp Control - Right111
High Beam Headlamp Control - Left222
High Beam Headlamp Control - Right222
Turn Signal/Multifunction Switch Headlamps OFF SignalB257A 0033
Turn Signal/Multifunction Switch Headlamps ON SignalB257A 0033
Turn Signal/Multifunction Switch Flash To Pass SignalB3806 0033
Turn Signal/Multifunction Switch High Beam SignalB3650 0833
Headlamp Ground - Left1, 2
Headlamp Ground - Right1, 2
Turn Signal/Multifunction Switch Ground3
1. Headlamps Malfunction - Low Beam 2. Headlamps Malfunction - High Beam 3. Turn Signal/Multifunction Switch Malfunction

For headlamp operation, the body control module (BCM) monitors 3 signal circuits from the turn signal/multifunction switch. When the turn signal/multifunction switch is in the AUTO position, the 3 signal circuits are open and the BCM relies on the ambient light sensor input to turn the headlamps and daytime running lamps (DRLs) ON and OFF. When the turn signal/multifunction switch is placed in the OFF position, the turn signal/multifunction switch headlamps OFF signal circuit is grounded, indicating to the BCM that the exterior lamps should be turned OFF. With the turn signal/multifunction switch in the PARK LAMPS position, the turn signal/multifunction switch park lamps ON signal circuit is grounded, indicating that the park lamps have been requested. When the turn signal/multifunction switch is in the HEADLAMP position, both the turn signal/multifunction switch park lamps ON signal circuit and the turn signal/multifunction switch headlamps ON signal circuit are grounded. The BCM responds by commanding the park lamps and headlamps ON.

The high beam and flash to pass functions are contained within the turn signal/multifunction switch. The BCM provides the turn signal/multifunction switch with 2 signal circuits, the high beam signal circuit and the flash to pass signal circuit. When the low beam headlamps are ON and the turn signal/multifunction switch is placed in the high beam position, ground is applied to the BCM through the high beam signal circuit. The BCM responds to the high beam request by applying ground to the 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 high beam fuses to the high beam control circuits illuminating the high beam headlamps.

When the turn signal/multifunction switch is momentarily placed in the flash to pass position, ground is applied to the BCM through the flash to pass signal circuit. The BCM responds by applying ground to the high beam relay control circuit which energizes the high beam relay illuminating the high beams for a brief moment or until the flash to pass switch is released.

Schematic Reference

  1. «Headlights/Daytime Running Lights (DRL) Schematics»(/cadillac/elr/i-2013-2015/remont/exterior-lights/#lighting-system)
  2. «Body Control System Schematics»(/cadillac/elr/i-2013-2015/remont/communication-devices/#data-communication-system-schematic-wiring-diagrams)

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Vehicle in Service Mode.
  2. Verify the scan tool Headlamps On Switch parameter changes between Active and Inactive while commanding the headlamps ON and OFF with the turn signal/multifunction switch. If the parameter does not change Refer to Headlamp Switch Malfunction. If the parameter changes
  3. Verify the scan tool Automatic Headlamps Disable Switch parameter changes between Active and Inactive while commanding the automatic lamp control ON and OFF with the turn signal/multifunction switch. If the parameter does not change Refer to Headlamp Switch Malfunction. If the parameter changes
  4. Verify the scan tool Headlamps Flash Switch parameter changes between Active and Inactive while commanding the flash to pass ON and OFF with the turn signal/multifunction switch. If the parameter does not change Refer to Turn Signal/Multifunction Switch Malfunction. If the parameter changes
  5. Verify the scan tool High Beam Select Switch parameter changes between Active and Inactive while commanding the high beams ON and OFF with the turn signal/multifunction switch. If the parameter does not change Refer to Turn Signal/Multifunction Switch Malfunction. If the parameter changes
  6. Verify the left low beam headlamp lamp turns ON and OFF when commanding the Left Headlamp Low Beam ON and OFF with a scan tool. If the left low beam headlamp does not turn ON and OFF Refer to Headlamps Malfunction - Low Beam. If the left low beam headlamp turns ON and OFF
  7. Verify the right low headlamp turns ON and OFF when commanding the Right Headlamp Low Beam ON and OFF with a scan tool. If the right low beam headlamp does not turn ON and OFF Refer to Headlamps Malfunction - Low Beam. If the right low beam headlamp turns ON and OFF
  8. Low beam headlamps ON, verify the high beams turn ON and OFF when commanding the High Beams ON and OFF with a scan tool. If the high beams do not turn ON and OFF Refer to Headlamps Malfunction - High Beam. If the high beams turn ON and OFF
  9. Verify the high beam indicator on the instrument cluster turns ON and OFF while commanding the All Indicators Test ON and OFF with a scan tool. If the high beam indicator does not turn ON and OFF Refer to High Beam Indicator Malfunction. If the high beam indicator turns ON and OFF
  10. All OK.

Headlamp Switch Malfunction

  1. Vehicle OFF, scan tool disconnected, all doors closed, all accessories OFF, disconnect the harness connector at the S78 Turn Signal/Multifunction Switch. It may take up to 2 minutes for all vehicle systems to power down.
  2. Test for less than 10 ohms between the ground circuit terminal 6 and ground. If 10 ohms or greater Vehicle OFF. Test for less than 2 ohms in the ground circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, repair the open/high resistance in the ground connection. If less than 10 ohms
  3. Vehicle in Service Mode.
  4. Verify the scan tool Automatic Headlamps Disable Switch parameter is Inactive. If not Inactive Vehicle OFF, disconnect the X1 harness connector at the K9 Body Control Module. Test for infinite resistance between the signal circuit terminal 9 and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance, replace the K9 Body Control Module. If Inactive
  5. Install a 3 A fused jumper wire between the signal circuit terminal 9 and ground.
  6. Verify the scan tool Automatic Headlamps Disable Switch parameter is Active. If not Active Vehicle OFF, disconnect the X1 harness connector at the K9 Body Control Module, vehicle in Service Mode. Test for less than 1 V between the signal circuit terminal 9 and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V Test for less than 2 ohms in the signal circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K9 Body Control Module. If Active
  7. Verify the scan tool Park Lamps Switch parameter is Inactive. If not Inactive Vehicle OFF, disconnect the X1 harness connector at the K9 Body Control Module. Test for infinite resistance between the signal circuit terminal 7 and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance, replace the K9 Body Control Module. If Inactive
  8. Install a 3 A fused jumper wire between the signal circuit terminal 7 and ground.
  9. Verify the scan tool Park Lamps Switch parameter is Active. If not Active Vehicle OFF, disconnect the X1 harness connector at the K9 Body Control Module, vehicle in Service Mode. Test for less than 1 V between the signal circuit terminal 7 and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V Test for less than 2 ohms in the signal circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K9 Body Control Module. If Active
  10. Verify the scan tool Headlamps On Switch parameter is Inactive. If not Inactive Vehicle OFF, disconnect the X1 harness connector at the K9 Body Control Module. Test for infinite resistance between the signal circuit terminal 2 and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance, replace the K9 Body Control Module. If Inactive
  11. Install a 3 A fused jumper wire between the signal circuit terminal 2 and ground.
  12. Verify the scan tool Headlamps On Switch parameter is Active. If not Active Vehicle OFF, disconnect the X1 harness connector at the K9 Body Control Module, vehicle in Service Mode. Test for less than 1 V between the signal circuit terminal 2 and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V Test for less than 2 ohms in the signal circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K9 Body Control Module. If Active
  13. Test or replace the S78 Turn Signal/Multifunction Switch.

Turn Signal/Multifunction Switch Malfunction

  1. Vehicle OFF, scan tool disconnected, all doors closed, all accessories OFF, disconnect the harness connector at the S78 Turn Signal/Multifunction Switch. It may take up to 2 minutes for all vehicle systems to power down.
  2. Test for less than 10 ohms between the ground circuit terminal 6 and ground. If 10 ohms or greater Vehicle OFF. Test for less than 2 ohms in the ground circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, repair the open/high resistance in the ground connection. If less than 10 ohms
  3. Vehicle in Service Mode.
  4. Verify the scan tool High Beam Select Switch parameter is Inactive. If not Inactive Vehicle OFF, disconnect the X3 harness connector at the K9 Body Control Module. Test for infinite resistance between the signal circuit terminal 11 and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance, replace the K9 Body Control Module. If Inactive
  5. Install a 3 A fused jumper wire between the signal circuit terminal 11 and ground.
  6. Verify the scan tool High Beam Select Switch parameter is Active. If not Active Vehicle OFF, disconnect the X3 harness connector at the K9 Body Control Module, vehicle in Service Mode. Test for less than 1 V between the signal circuit terminal 11 and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V Test for less than 2 ohms in the signal circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K9 Body Control Module. If Active
  7. Verify the scan tool Headlamps Flash Switch parameter is Inactive. If not Inactive Vehicle OFF, disconnect the X3 harness connector at the K9 Body Control Module. Test for infinite resistance between the signal circuit terminal 12 and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance, replace the K9 Body Control Module. If Inactive
  8. Install a 3 A fused jumper wire between the signal circuit terminal 12 and ground.
  9. Verify the scan tool Headlamps Flash Switch parameter is Active. If not Active Vehicle OFF, disconnect the X3 harness connector at the K9 Body Control Module, vehicle in Service Mode. Test for less than 1 V between the signal circuit terminal 12 and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V Test for less than 2 ohms in the signal circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K9 Body Control Module. If Active
  10. Test or replace the S78 Turn Signal/Multifunction Switch.

Headlamps Malfunction - Low Beam

  1. Vehicle OFF, disconnect the X1 harness connector at the K9 Body Control Module, vehicle in Service Mode.
  2. Verify a test lamp illuminates between the B+ circuit terminal 2 and ground. If the test lamp does not illuminate and the circuit fuse is good Test for less than 2 ohms in the B+ circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, verify the fuse is not open and there is voltage at the fuse. If the test lamp does not illuminate and the circuit fuse is open Test for infinite resistance between the B+ circuit and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance, replace the K9 Body Control Module If the test lamp illuminates
  3. Verify a test lamp illuminates between the B+ circuit terminal 3 and ground. If the test lamp does not illuminate and the circuit fuse is good Test for less than 2 ohms in the B+ circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, verify the fuse is not open and there is voltage at the fuse. If the test lamp does not illuminate and the circuit fuse is open Test for infinite resistance between the B+ circuit and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance, replace the K9 Body Control Module If the test lamp illuminates
  4. Vehicle OFF, connect the X1 harness connector at the K9 Body Control Module.
  5. Vehicle OFF, exterior lamps OFF, disconnect the harness connector at the appropriate E13 Headlamp.
  6. Test for less than 5 ohms between the ground circuit terminal 6 and ground. If 5 ohms or greater Vehicle OFF. Test for less than 2 ohms in the ground circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, repair the open/high resistance in the ground connection. If less than 5 ohms
  7. Connect a test lamp between the control circuit terminal 2 and ground, vehicle in Service Mode.
  8. Verify the test lamp turns ON and OFF when commanding the appropriate Headlamp Low Beam ON and OFF with a scan tool. If the test lamp is always OFF Vehicle OFF, disconnect the X4 harness connector at the K9 Body Control Module Test for infinite resistance between the control circuit and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance Test for less than 2 ohms in the control circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K9 Body Control Module. If the test lamp is always ON Vehicle OFF, disconnect the X4 harness connector at the K9 Body Control Module, vehicle in Service Mode. Test for less than 1 V between the control circuit terminal and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V, replace the K9 Body Control Module. If the test lamp turns ON and OFF
  9. Test or replace the E4 Headlamp - Low Beam.

Headlamps Malfunction - High Beam

  1. Vehicle OFF, disconnect the X5 harness connector at the K9 Body Control Module, vehicle in Service Mode.
  2. Verify a test lamp illuminates between the control circuit terminal 18 and ground. If the test lamp does not illuminate Vehicle OFF, disconnect the X2 harness connector at the X50A Fuse Block - Underhood. Test for infinite resistance between the control circuit terminal and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance Test for less than 2 ohms in the control circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the X50A Fuse Block - Underhood. If the test lamp illuminates
  3. Vehicle OFF, connect a 3 A fused jumper between the control circuit terminal 18 and ground.
  4. Remove the left high beam fuse (F22UA) at the X50A Fuse Block - Underhood, vehicle in Service Mode.
  5. Verify a test lamp illuminates between the left high beam fuse (F22UA) B+ switch control terminal and ground. If the test lamp does not illuminate Vehicle OFF, disconnect the X2 harness connector at the X50A Fuse Block - Underhood, vehicle in Service Mode. Test for less than 1 V between the control circuit terminal 18 and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V, replace the X50A Fuse Block - Underhood. If the test lamp illuminates
  6. Vehicle OFF, connect the X5 harness connector at the K9 Body Control Module.
  7. Install the left high beam fuse (F22UA) at the X50A Fuse Block - Underhood.
  8. Vehicle OFF, exterior lamps OFF, disconnect the harness connector at the appropriate E13 Headlamp.
  9. Test for less than 5 ohms between the ground circuit terminal 3 and ground. If 5 ohms or greater Vehicle OFF. Test for less than 2 ohms in the ground circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, repair the open/high resistance in the ground connection. If less than 5 ohms
  10. Connect a test lamp between the control circuit terminal 1 and ground, vehicle in Service Mode.
  11. Verify the test lamp turns ON and OFF when commanding the High Beams ON and OFF with a scan tool. If the test lamp is always OFF Vehicle OFF, disconnect the X1 harness connector at the X50A Fuse Block - Underhood. Test for infinite resistance between the control circuit and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance Test for less than 2 ohms in the control circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the X50A Fuse Block - Underhood. If the test lamp is always ON Vehicle OFF, disconnect the X1 harness connector at the X50A Fuse Block - Underhood, vehicle in Service Mode. Test for less than 1 V between the control circuit terminal and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V, replace the X50A Fuse Block - Underhood. If the test lamp turns ON and OFF
  12. Test or replace the E4 Headlamp - High Beam.

High Beam Indicator Malfunction

  1. Vehicle in Service Mode.
  2. Verify the high beam indicator turns ON and OFF when commanding the Instrument Cluster All Indicators Test ON and OFF with a scan tool. If the high beam indicator is always OFF or remains ON Replace the P16 Instrument Cluster. If the high beam indicator turns ON and OFF
  3. Replace the K9 Body Control Module.

Perform the Diagnostic Repair Verification after completing the repair.

  1. «Headlamp Replacement»(/cadillac/elr/i-2013-2015/remont/exterior-lights/#lighting-system)
  2. «Turn Signal Switch Replacement»(/cadillac/elr/i-2013-2015/remont/steering-column-switches/#steering-wheel-and-steering-column)
  3. «Accessory Wiring Junction Block Replacement»(/cadillac/elr/i-2013-2015/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-repair-instructions)
  4. «Control Module References»(/cadillac/elr/i-2013-2015/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM and Instrument Cluster replacement, programming, and setup
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/elr/i-2013-2015/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/elr/i-2013-2015/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/elr/i-2013-2015/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
F5DR (BCM/EXT LIGHTS) Fuse B+B270A 01B270A 01
F54UA Fuse B+444
Instrument Panel Dimmer Switch B+B1395 03, B3600 03B3600 031B1395 07
Instrument Panel Dimmer Switch SignalB3600 03B3600 03B3600 07, 1
LED Backlight Dimming Control Terminal 8 X2B2610 02B2610 04, 1B2610 01, 1
LED Backlight Dimming Control Terminal 9 X7B2610 02B2610 04, 1B2610 01, 1
Park Assist Switch Amber LED Backlight Dimming Control Terminal 5 X1B2625 0277
Vehicle ON/OFF Switch Dimming Control333
Instrument Panel Dimmer Switch Low Reference111
Park Assist Switch Amber LED Low Reference777
Charge Port Door Open Request Switch Ground2
Dome/Reading Lamps - Front Ground2
Driver Information Center Switch Ground2
Driver Mode Select Switch Ground (LHD)5
Door Lock Switch Ground (RHD)6
Multifunction Switch - Overhead Console Ground2
Outside Rearview Mirror Switch Ground2
Passenger Air Bag Disable Indicator Backlighting Ground4
Park Brake Control Switch Ground2
Radio/HVAC Controls Ground2
Refuel Request Switch Ground2
Steering Wheel Controls Switch - Left Ground2
Steering Wheel Controls Switch - Right Ground2
Vehicle ON/OFF Switch Ground3
1. Dimmer Switch Malfunction 2. Interior Backlighting Malfunction 3. Vehicle ON/OFF Switch Backlighting Malfunction 4. Passenger Air Bag Disable Indicator Backlighting Malfunction 5. Driver Mode Select Switch Backlighting Malfunction 6. Door Lock Switch Backlighting Malfunction 7. Park Assist Switch Amber LED Backlighting Malfunction

The instrument panel dimmer switch is used to increase and decrease the brightness of the interior backlighting components. The instrument panel dimmer switch provides a voltage signal to the body control module (BCM) that will increase as the brightness of the lights are increased and decrease as the brightness of the lights are decreased. The BCM provides B+, low reference, and signal, circuits to the instrument panel dimmer switch. When the instrument panel dimmer switch is placed in the desired position, the dimmed voltage setting is applied from the instrument panel dimmer switch through the instrument panel dimmer switch signal circuit to the BCM. The BCM interprets the signal and applies a pulse width modulated (PWM) voltage through the LED dimming control circuits illuminating the interior backlighting to the requested level of brightness.

Schematic Reference

  1. «Interior Lights Dimming Schematics»(/cadillac/elr/i-2013-2015/remont/exterior-lights/#lighting-system)
  2. «SIR Schematics»(/cadillac/elr/i-2013-2015/remont/airbag/#supplemental-inflatable-restraint-system)
  3. «Body Control System Schematics»(/cadillac/elr/i-2013-2015/remont/communication-devices/#data-communication-system-schematic-wiring-diagrams)

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Vehicle in Service Mode, park lamps ON.
  2. Verify the scan tool LED Backlight Dimming Command parameter changes between a high percentage to a low percentage while operating the dimmer switch from high to low. If the parameter does not change Refer to Dimmer Switch Malfunction. If the parameter changes
  3. Verify the backlighting components turn ON and OFF while commanding the LED Backlight Dimming ON and OFF with a scan tool. If the backlighting components do not turn ON and OFF Refer to Interior Backlighting Malfunction. If the backlighting components turn ON and OFF
  4. Verify the vehicle ON/OFF switch backlighting changes from LOW to HIGH while adjusting the backlighting from low to high with the dimmer switch. If the vehicle ON/OFF switch backlighting does not change from LOW to HIGH Refer to Vehicle ON/OFF Switch Backlighting Malfunction. If the vehicle ON/OFF switch backlighting changes from LOW to HIGH
  5. Verify the door lock switch backlighting changes from LOW to HIGH while adjusting the backlighting from low to high with the dimmer switch. If the door lock switch backlighting does not change from LOW to HIGH Refer to Switch Backlighting Malfunction. If the door lock switch backlighting changes from LOW to HIGH
  6. Verify the driver mode select switch backlighting changes from LOW to HIGH while adjusting the backlighting from low to high with the dimmer switch. If the driver mode select switch backlighting does not change from LOW to HIGH Refer to Switch Backlighting Malfunction. If the driver mode select switch backlighting changes from LOW to HIGH
  7. Park assist ON, verify the park assist switch amber LED backlighting changes from LOW to HIGH while adjusting the backlighting from low to high with the dimmer switch. If the park assist switch amber LED backlighting does not change from LOW to HIGH Refer to Park Assist Switch Amber LED Backlighting Malfunction. If the park assist switch backlighting changes from LOW to HIGH
  8. Verify the phrase PASSENGER AIR BAG is illuminated on the Passenger Air Bag Disable Indicator. If the phrase PASSENGER AIR BAG is not illuminated Refer to Passenger Air Bag Disable Indicator Backlighting Malfunction. If the phrase PASSENGER AIR BAG is illuminated
  9. All OK.

Dimmer Switch Malfunction

  1. Vehicle OFF, disconnect the harness connector at the S36 Instrument Panel Dimmer Switch, vehicle in Service Mode.
  2. Verify a test lamp illuminates between the low reference circuit terminal 1 and B+. If the test lamp does not illuminate Vehicle OFF, disconnect the X1 harness connector at the K9 Body Control Module, vehicle in Service Mode. Test for less than 1 V between the low reference circuit terminal 1 and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V Test for less than 2 ohms in the low reference circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K9 Body Control Module. If the test lamp illuminates
  3. Test for B+ between the B+ circuit terminal 6 and ground. If less than B+ Vehicle OFF, disconnect the X1 harness connector at the K9 Body Control Module. Test for infinite resistance between the B+ reference circuit and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance Test for less than 2 ohms in the B+ reference circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K9 Body Control Module. If B+
  4. Verify a test lamp does not illuminate between the B+ circuit terminal 6 and ground. If the test lamp illuminates Vehicle OFF, disconnect the X1 harness connector at the K9 Body Control Module, vehicle in Service Mode. Test for less than 1 V between the B+ circuit terminal 6 and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V, replace the K9 Body Control Module. If the test lamp does not illuminate
  5. Verify the scan tool LED Backlight Dimming Command parameter is greater than 40%. If 40% or less Vehicle OFF, disconnect the X2 harness connector at the K9 Body Control Module, vehicle in Service Mode. Test for less than 1 V between the signal circuit terminal 2 and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V, replace the K9 Body Control Module. If greater than 40%
  6. Install a 3 A fused jumper wire between the signal circuit terminal 2 and the B+ circuit terminal 6.
  7. Verify the scan tool LED Backlight Dimming Command parameter is less than 30%. If 30% or greater Vehicle OFF, disconnect the X2 harness connector at the K9 Body Control Module. Test for infinite resistance between the signal circuit and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance Test for less than 2 ohms in the signal circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K9 Body Control Module. If less than 30%
  8. Test or replace the S36 Instrument Panel Dimmer Switch.

Interior Backlighting Malfunction

  1. Vehicle OFF, all doors closed, all accessories OFF, disconnect the harness connector at the component with inoperative backlighting. It may take up to 2 minutes for all vehicle systems to power down.
  2. Test for less than 15 ohms between the appropriate ground circuit terminal and ground. If 15 ohms or greater Vehicle OFF. Test for less than 2 ohms in the ground circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, repair the open/high resistance in the ground connection. If less than 15 ohms
  3. Connect a test lamp between the appropriate control circuit terminal and ground, vehicle in Service Mode.
  4. Verify the test lamp turns ON and OFF when commanding the LED Backlight Dimming ON and OFF with a scan tool. If the test lamp is always OFF Vehicle OFF, disconnect the X2 and X7 harness connectors at the K9 Body Control Module.. Test for infinite resistance between the control circuit and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance Test for less than 2 ohms in the control circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K9 Body Control Module.. If the test lamp is always ON Vehicle OFF, disconnect the X2 and X7 harness connectors at the K9 Body Control Module., vehicle in Service Mode. Test for less than 1 V between the control circuit terminal and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V, replace the K9 Body Control Module.. If the test lamp turns ON and OFF
  5. Test or replace the component with inoperative backlighting.

Vehicle ON/OFF Switch Backlighting Malfunction

  1. Vehicle OFF, scan tool disconnected, all doors closed, all accessories OFF, disconnect the harness connector at the S83 Vehicle ON/OFF Switch. It may take up to 2 minutes for all vehicle systems to power down.
  2. Test for less than 5 ohms between the ground circuit terminal 4 and ground. If 5 ohms or greater Vehicle OFF. Test for less than 2 ohms in the ground circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, repair the open/high resistance in the ground connection. If less than 5 ohms
  3. Connect a test lamp between the control circuit terminal 8 and ground, vehicle in Service Mode, park lamps ON.
  4. Verify the test lamp changes from LOW to HIGH as the dimmer switch is activated from LOW to HIGH. If the test lamp is always OFF Vehicle OFF, disconnect the X7 harness connector at the K9 Body Control Module. Test for infinite resistance between the control circuit and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance Test for less than 2 ohms in the control circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K9 Body Control Module. If the test lamp is always ON full intensity Vehicle OFF, disconnect the X7 harness connector at the K9 Body Control Module, vehicle in Service Mode. Test for less than 1 V between the control circuit terminal and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V, replace the K9 Body Control Module. If the test lamp changes from LOW to HIGH
  5. Test or replace the S83 Vehicle ON/OFF Switch.

Switch Backlighting Malfunction

  1. Vehicle OFF, scan tool disconnected, all doors closed, all accessories OFF, disconnect the harness connector at the S126 Driver Mode Select Switch. It may take up to 2 minutes for all vehicle systems to power down.
  2. Test for less than 15 ohms between the ground circuit terminal 4 and ground. If 15 ohms or greater Vehicle OFF. Test for less than 2 ohms in the ground circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, repair the open/high resistance in the ground connection. If less than 15 ohms
  3. Connect a test lamp between the control circuit terminal 3 and ground, vehicle in Service Mode, park lamps ON.
  4. Verify the test lamp changes from LOW to HIGH as the dimmer switch is activated from LOW to HIGH. If the test lamp is always OFF Vehicle OFF, disconnect the harness connector at the A20 Radio/HVAC Controls. Test for infinite resistance between the control circuit and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance Test for less than 2 ohms in the control circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the A20 Radio/HVAC Controls. If the test lamp is always ON full intensity Vehicle OFF, disconnect the harness connector at the A20 Radio/HVAC Controls, vehicle in Service Mode. Test for less than 1 V between the control circuit terminal and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V, replace the A20 Radio/HVAC Controls. If the test lamp changes from LOW to HIGH
  5. Test or replace the S126 Driver Mode Select Switch.

Park Assist Switch Amber LED Backlighting Malfunction

  1. Vehicle OFF, disconnect the harness connector at the S48B Multifunction Switch - Overhead Console.
  2. Connect a test lamp between the control circuit terminal 3 and ground.
  3. Verify the test lamp turns ON and OFF when commanding the LED Backlight Dimming ON and OFF with a scan tool. If the test lamp is always OFF Vehicle OFF, disconnect the X1 harness connector at the K9 Body Control Module. Test for infinite resistance between the control circuit and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance Test for less than 2 ohms in the control circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K9 Body Control Module. If the test lamp is always ON Vehicle OFF, disconnect the X1 harness connector at the K9 Body Control Module, vehicle in Service Mode. Test for less than 1 V between the control circuit terminal and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V, replace the K9 Body Control Module. If the test lamp turns ON and OFF
  4. Vehicle OFF.
  5. Connect a test lamp between the control circuit terminal 3 and low reference circuit terminal 3.
  6. Verify the test lamp turns ON and OFF when commanding the LED Backlight Dimming ON and OFF with a scan tool. If the test lamp is always OFF Vehicle OFF, disconnect the X1 harness connector at the K41 Front and Rear Parking Assist Control Module, vehicle in Service Mode. Test for less than 1 V between the low reference circuit terminal and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V Test for less than 2 ohms in the low reference circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K41 Front and Rear Parking Assist Control Module. If the test lamp turns ON and OFF
  7. Test or replace the S48B Multifunction Switch - Overhead Console.

Passenger Air Bag Disable Indicator Backlighting Malfunction

  1. Vehicle OFF, scan tool disconnected, all doors closed, all accessories OFF, disconnect the harness connector at the P14 Passenger Air Bag Disable Indicator. It may take up to 2 minutes for all vehicle systems to power down.
  2. Test for less than 5 ohms between the ground circuit terminal 2 and ground. If 5 ohms or greater Vehicle OFF. Test for less than 2 ohms in the ground circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, repair the open/high resistance in the ground connection. If less than 5 ohms
  3. Connect a test lamp between the control circuit terminal 4 and ground, vehicle in Service Mode.
  4. Verify the test lamp turns ON and OFF while turning the vehicle mode switch between Service Mode and Vehicle OFF. If the test lamp is always OFF Vehicle OFF, remove the F54UA at the X50A Fuse Block - Underhood. Test for infinite resistance between the control circuit and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance Test for less than 2 ohms in the control circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the X50A Fuse Block - Underhood. If the test lamp is always ON Vehicle OFF, remove the F54UA at the X50A Fuse Block - Underhood, vehicle in Service Mode. Test for less than 1 V between the control circuit terminal and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V, replace the X50A Fuse Block - Underhood. If the test lamp turns ON and OFF
  5. Test or replace the P14 Passenger Air Bag Disable Indicator.

Perform the Diagnostic Repair Verification after completing the repair.

  1. «Outside Rearview Mirror Remote Control Switch Replacement»(/cadillac/elr/i-2013-2015/remont/mirrors/#mirror-system)
  2. «Radio Control Assembly Replacement»(/cadillac/elr/i-2013-2015/remont/entertainment-systems/#cellular-system-entertainment-system-and-navigation-system)
  3. «Garage Door Opener Transmitter Pushbutton Replacement»(/cadillac/elr/i-2013-2015/remont/door-locks-anti-theft-systems/#keyless-entry-system-and-remote-functions)
  4. «Instrument Panel Airbag Arming Status Display Replacement»(/cadillac/elr/i-2013-2015/remont/airbag/#supplemental-inflatable-restraint-system)
  5. «Center Reading and Courtesy Lamp Replacement»(/cadillac/elr/i-2013-2015/remont/exterior-lights/#lighting-system)
  6. «Parking Brake Switch Replacement»(/cadillac/elr/i-2013-2015/remont/parking-brake-system/#parking-brake-system)
  7. «Fuel Tank Filler Door Lock Release Switch Replacement»(/cadillac/elr/i-2013-2015/remont/door-locks-anti-theft-systems/#power-door-lock-system-and-release-systems)
  8. «Control Module References»(/cadillac/elr/i-2013-2015/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM replacement, programming, and setup
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/elr/i-2013-2015/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/elr/i-2013-2015/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/elr/i-2013-2015/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
F6DR (APO/EXT LIGHTS) Fuse B+B3867 01, B3867 04, B3949 01, B3949 04B3867 01, B3867 04, B3949 01, B3949 04
Turn Signal/Multifunction Switch Park Lamps ON Signal2B257A 002
License Plate Lamp ControlB3883 02B3883 01, B3883 04B3883 01
Park Lamps Control - Left FrontB2585 02B2585 01, B2585 04B2585 01, B2585 04
Park Lamps Control - Right FrontB3867 02B3867 01, B3867 04B3867 01, B3867 04
Park Lamps Control - Left Rear111
Park Lamps Control - Right Rear111
License Plate Lamp Ground - Right1
License Plate Lamp Ground - Left1
Park Lamp Ground - Left FrontB2585 01, B2585 04, B3948 01, B3948 04
Park Lamp Ground - Right FrontB3867 01, B3867 04, B3949 01, B3949 04
Tail Lamp Ground - Left1
Tail Lamp Ground - Right1
Turn Signal/Multifunction Switch Ground2
1. Park, License, and/or Tail Lamps Malfunction 2. Park Lamp Switch Malfunction

When the turn signal/multifunction switch is placed in the HEAD or PARK position, ground is applied to the park lamps ON signal circuit to the body control module (BCM). The BCM responds by applying voltage to the park lamps, tail lamps, and license lamps control circuits illuminating the park, tail, and license lamps.

Schematic Reference

  1. «Exterior Lights Schematics»(/cadillac/elr/i-2013-2015/remont/exterior-lights/#lighting-system)
  2. «Body Control System Schematics»(/cadillac/elr/i-2013-2015/remont/communication-devices/#data-communication-system-schematic-wiring-diagrams)

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Vehicle in Service Mode.
  2. Verify the scan tool Park Lamp Switch parameter changes between Active and Inactive while commanding the park lamps ON and OFF with the turn signal/multifunction switch. If the parameter does not change Refer to Park Lamp Switch Malfunction. If the parameter changes
  3. Verify the left front park lamp turns ON and OFF when commanding the Left Front Park Lamp ON and OFF with a scan tool. If the left front park lamp does not turn ON and OFF Refer to Park Lamps Malfunction. If the left front park lamp turns ON and OFF
  4. Verify the left rear park lamp turns ON and OFF when commanding the Left Rear Park Lamp ON and OFF with a scan tool. If the left rear park lamp does not turn ON and OFF Refer to Park Lamps Malfunction. If the left rear park lamp turns ON and OFF
  5. Verify the right front park lamp turns ON and OFF when commanding the Right Front Park ON and OFF with a scan tool. If the right front park lamp does not turn ON and OFF Refer to Park Lamps Malfunction. If the right front park lamp turns ON and OFF
  6. Verify the right rear park lamp turns ON and OFF when commanding the Right Rear Park ON and OFF with a scan tool. If the right rear park lamp does not turn ON and OFF Refer to Park Lamps Malfunction. If the right rear park lamp turns ON and OFF
  7. Verify the license plate lamps turn ON and OFF when commanding the License Plate Lamps ON and OFF with a scan tool. If the license plate lamps do not turn ON and OFF Refer to License Plate Lamps Malfunction. If the license plate lamps turn ON and OFF
  8. All OK.

Park Lamp Switch Malfunction

  1. Vehicle OFF, all doors closed, all accessories OFF, disconnect the harness connector at the S78 turn signal/multifunction switch. It may take up to 2 minutes for all vehicle systems to power down.
  2. Test for less than 10 ohms between the ground circuit terminal 6 and ground. If 10 ohms or greater Vehicle OFF. Test for less than 2 ohms in the ground circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, repair the open/high resistance in the ground connection. If less than 10 ohms
  3. Vehicle in Service Mode.
  4. Verify the scan tool Park Lamps Switch parameter is Inactive. If not Inactive Vehicle OFF, disconnect the X1 harness connector at the K9 body control module. Test for infinite resistance between the signal circuit terminal 7 and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance, replace the K9 body control module. If Inactive
  5. Install a 3 A fused jumper wire between the signal circuit terminal 7 and the ground circuit terminal 6.
  6. Verify the scan tool Park Lamps Switch parameter is Active. If not Active Vehicle OFF, disconnect the X1 harness connector at the K9 body control module, vehicle in Service Mode. Test for less than 1 V between the signal circuit terminal 7 and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V Test for less than 2 ohms in the signal circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K9 body control module. If Active
  7. Test or replace the S78 turn signal/multifunction switch.

Park Lamps Malfunction

  1. Vehicle OFF, exterior lamps OFF, disconnect the harness connector at the inoperative E4 park lamp.
  2. Test for less than 5 ohms between the appropriate ground circuit terminal listed below and ground. E4N park/turn signal lamp - left terminal 1 E4P park/turn signal lamp - right terminal 1 E42L tail lamp assembly - left terminal 4 E42R tail lamp assembly - right terminal 4 If 5 ohms or greater Vehicle OFF. Test for less than 2 ohms in the ground circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, repair the open/high resistance in the ground connection. If less than 5 ohms
  3. Connect a test lamp between the appropriate control circuit terminal listed below and ground, vehicle in Service Mode. E4N park/turn signal lamp - left terminal 2 E4P park/turn signal lamp - right terminal 2 E42L tail lamp assembly - left terminal 2 E42R tail lamp assembly - right terminal 2
  4. Verify the test lamp turns ON and OFF when commanding the appropriate Park Lamps ON and OFF with a scan tool. If the test lamp is always OFF Vehicle OFF, disconnect the appropriate harness connector listed below at the K9 body control module. X4 X5 Test for infinite resistance between the control circuit and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance Test for less than 2 ohms in the control circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K9 body control module. If the test lamp is always ON Vehicle OFF, disconnect the appropriate harness connector listed below at the K9 body control module, vehicle in Service Mode. X4 X5 Test for less than 1 V between the control circuit terminal and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V, replace the K9 body control module. If the test lamp turns ON and OFF
  5. Test or replace the appropriate E4 park lamp.

License Plate Lamps Malfunction

  1. Vehicle OFF, exterior lamps OFF, remove both E7 license plate lamp bulbs.
  2. Test for less than 5 ohms between each ground circuit terminal 2 and ground. If 5 ohms or greater Vehicle OFF. Test for less than 2 ohms in the ground circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, repair the open/high resistance in the ground connection. If less than 5 ohms
  3. Connect a test lamp between the E7L license plate lamp - left control circuit terminal 1 and ground, vehicle in Service Mode.
  4. Verify the test lamp turns ON and OFF when commanding the License Plate Lamps ON and OFF with a scan tool. If the test lamp is always OFF Vehicle OFF, disconnect the X4 harness connector at the K9 body control module. Test for infinite resistance between the control circuit and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance Test for less than 2 ohms in the control circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K9 body control module. If the test lamp is always ON Vehicle OFF, disconnect the X4 harness connector at the K9 body control module, vehicle in Service Mode. Test for less than 1 V between the control circuit terminal and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V, replace the K9 body control module. If the test lamp turns ON and OFF
  5. Connect a test lamp between the E7R license plate lamp - right control circuit terminal 1 and ground, vehicle in Service Mode.
  6. Verify the test lamp turns ON and OFF when commanding the License Plate Lamps ON and OFF with a scan tool. If the test lamp is always OFF Vehicle OFF, disconnect the X4 harness connector at the K9 body control module. Test for infinite resistance between the control circuit and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance Test for less than 2 ohms in the control circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K9 body control module. If the test lamp turns ON and OFF
  7. Test or replace the appropriate E7 license plate lamp bulb.

Perform the Diagnostic Repair Verification after completing the repair.

  1. «Headlamp Replacement»(/cadillac/elr/i-2013-2015/remont/exterior-lights/#lighting-system)
  2. «Rear License Plate Lamp Replacement»(/cadillac/elr/i-2013-2015/remont/exterior-lights/#lighting-system)
  3. «Tail Lamp Replacement»(/cadillac/elr/i-2013-2015/remont/exterior-lights/#lighting-system)
  4. «Turn Signal Switch Replacement»(/cadillac/elr/i-2013-2015/remont/steering-column-switches/#steering-wheel-and-steering-column)
  5. «Control Module References»(/cadillac/elr/i-2013-2015/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM replacement, programming, and setup
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/elr/i-2013-2015/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/elr/i-2013-2015/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/elr/i-2013-2015/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
F5DR (BCM/EXT LIGHTS) Fuse B+B270A 01B270A 01
Cargo Lamp ControlB2570 0211
Cargo Lamp Ground1
1. Rear Compartment Lamp Malfunction

The body control module (BCM) applies battery voltage to the cargo lamp through the rear cargo lamp control circuit. When the BCM receives a rear liftgate open input from the rear liftgate latch, the BCM applies battery voltage to the rear cargo lamp control circuit illuminating the cargo lamp. In the event that the cargo lamp were to remain illuminated for more than 10 minutes with the vehicle ON/OFF switch in the OFF position and no doors opened, the BCM will deactivate the cargo lamp control circuit to prevent total battery discharge.

Schematic Reference

  1. «Interior Lights Schematics»(/cadillac/elr/i-2013-2015/remont/exterior-lights/#lighting-system)
  2. «Body Control System Schematics»(/cadillac/elr/i-2013-2015/remont/communication-devices/#data-communication-system-schematic-wiring-diagrams)

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Vehicle OFF, exterior lamps OFF, disconnect the harness connector at the E33 cargo lamp.
  2. Test for less than 5 ohms between the ground circuit terminal 2 and ground. If 5 ohms or greater Vehicle OFF. Test for less than 2 ohms in the ground circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, repair the open/high resistance in the ground connection. If less than 5 ohms
  3. Connect a test lamp between the control circuit terminal 1 and ground, vehicle in Service Mode.
  4. Verify the test lamp turns ON and OFF when commanding the Cargo Lamp ON and OFF with a scan tool. If the test lamp is always OFF Vehicle OFF, disconnect the X7 harness connector at the K9 body control module. Test for infinite resistance between the control circuit and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance Test for less than 2 ohms in the control circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K9 body control module. If the test lamp is always ON Vehicle OFF, disconnect the X7 harness connector at the K9 body control module, vehicle in Service Mode. Test for less than 1 V between the control circuit terminal and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V, replace the K9 body control module. If the test lamp turns ON and OFF
  5. Test or replace the E33 cargo lamp.

Perform the Diagnostic Repair Verification after completing the repair.

  1. «Rear Compartment Courtesy Lamp Replacement»(/cadillac/elr/i-2013-2015/remont/exterior-lights/#lighting-system)
  2. «Control Module References»(/cadillac/elr/i-2013-2015/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM replacement, programming, and setup
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/elr/i-2013-2015/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/elr/i-2013-2015/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/elr/i-2013-2015/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
F10DL (BCM/EXT LIGHTS) Fuse B+C0890 03, B101E 43, B1395 03, B1517 07, U0121 00, U0128 00, U0422 71C0890 03, B101E 43, B1395 03, B1517 07, U0121 00, U0128 00, U0422 71
Brake Pedal Position Sensor 5 V ReferenceC0277 06, C0890 03, U0422 71, C0561 71C0277 06, U0422 71, C0561 71C0277 07, C0890 07, U0422 71, C0561 71
Brake Pedal Position Sensor SignalC0277 06, U0422 71, C0561 71C0277 06, U0422 71, C0561 71C0277 07, C0890 07, U0422 71, C0561 71C0277 09
Center High Mounted Stop Lamp ControlB3884 02B3884 04B3884 01
Stop/Turn Signal Lamp Control - Left111
Stop/Turn Signal Lamp Control - Right111
Brake Pedal Position Sensor Low ReferenceC0277 06, U0422 71, C0561 711
Center High Mounted Stop Lamp Ground2
Tail/Stop Lamp Ground - Left1
Tail/Stop Lamp Ground - Right1
1. Stop Lamps Malfunction 2. Center High Mounted Stop Lamp Malfunction

The brake pedal position (BPP) sensor is used to sense the action of the driver application of the brake pedal. The BPP 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 BPP sensor. When the variable signal reaches a voltage threshold indicating the brakes have been applied, the BCM will apply battery voltage to the left and right stop lamp control circuits as well as the center high mounted stop lamp (CHMSL) control circuit illuminating the left and right stop lamps and the CHMSL.

Schematic Reference

  1. «Exterior Lights Schematics»(/cadillac/elr/i-2013-2015/remont/exterior-lights/#lighting-system)
  2. «Body Control System Schematics»(/cadillac/elr/i-2013-2015/remont/communication-devices/#data-communication-system-schematic-wiring-diagrams)

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Vehicle in Service Mode.
  2. Verify the scan tool Brake Pedal Applied parameter changes between Active and Inactive while pressing and releasing the brake pedal. If the parameter does not change Refer to Brake Pedal Position Sensor Malfunction. If the parameter changes
  3. Verify the left brake lamp turns ON and OFF when commanding the Left Rear Turn Signal/Brake Lamp ON and OFF with a scan tool. If the left brake lamp does not turn ON and OFF Refer to Stop Lamps Malfunction. If the left brake lamp turns ON and OFF
  4. Verify the right brake lamp turns ON and OFF when commanding the Right Rear Turn Signal/Brake Lamp ON and OFF with a scan tool. If the right brake lamp does not turn ON and OFF Refer to Stop Lamps Malfunction. If the right brake lamp turns ON and OFF
  5. Verify the center high mounted stop lamp turns ON and OFF when commanding the Center Brake Lamp ON and OFF with a scan tool. If the center high mounted stop does not turn ON and OFF Refer to Center High Mount Stop Lamp Malfunction. If the center high mounted stop turns ON and OFF
  6. All OK.

Brake Pedal Position Sensor Malfunction

  1. Vehicle OFF, disconnect the harness connector at the B22 brake pedal position sensor, vehicle in Service Mode.
  2. Test for less than 1 V between the low reference circuit terminal C and ground. If 1 V or greater Vehicle OFF, disconnect the X1 harness connector at the K9 body control module, vehicle in Service Mode. Test for less than 1 V between the low reference circuit and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V, replace the K9 body control module. If less than 1 V
  3. Test or replace the B22 brake pedal position sensor.

Stop Lamps Malfunction

  1. Vehicle OFF, exterior lamps OFF, disconnect the harness connector at the appropriate E42 tail lamp assembly.
  2. Test for less than 5 ohms between the ground circuit terminal 4 and ground. If 5 ohms or greater Vehicle OFF. Test for less than 2 ohms in the ground circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, repair the open/high resistance in the ground connection. If less than 5 ohms
  3. Connect a test lamp between the control circuit terminal 1 and ground, vehicle in Service Mode.
  4. Verify the test lamp turns ON and OFF when commanding the appropriate Rear Turn Signal/Brake Lamp ON and OFF with a scan tool. If the test lamp is always OFF Vehicle OFF, disconnect the appropriate harness connector listed below at the K9 body control module. X4 - right stop lamp X5 - left stop lamp Test for infinite resistance between the control circuit and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance Test for less than 2 ohms in the control circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K9 body control module. If the test lamp is always ON Vehicle OFF, disconnect the appropriate harness connector listed below at the K9 body control module, vehicle in Service Mode. X4 - right stop lamp X5 - left stop lamp Test for less than 1 V between the control circuit terminal and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V, replace the K9 body control module. If the test lamp turns ON and OFF
  5. Test or replace the appropriate E42 tail lamp assembly.

Center High Mount Stop Lamp Malfunction

  1. Vehicle OFF, exterior lamps OFF, disconnect the harness connector at the E6 center high mounted stop lamp.
  2. Test for less than 5 ohms between the ground circuit terminal 2 and ground. If 5 ohms or greater Vehicle OFF. Test for less than 2 ohms in the ground circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, repair the open/high resistance in the ground connection. If less than 5 ohms
  3. Connect a test lamp between the control circuit terminal 1 and ground, vehicle in Service Mode.
  4. Verify the test lamp turns ON and OFF when commanding the Center Brake Lamp ON and OFF with a scan tool. If the test lamp is always OFF Vehicle OFF, disconnect the X4 harness connector at the K9 body control module. Test for infinite resistance between the control circuit and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance Test for less than 2 ohms in the control circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K9 body control module. If the test lamp is always ON Vehicle OFF, disconnect the X4 harness connector at the K9 body control module, vehicle in Service Mode. Test for less than 1 V between the control circuit terminal and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V, replace the K9 body control module. If the test lamp turns ON and OFF
  5. Test or replace the E6 center high mounted stop lamp.

Perform the Diagnostic Repair Verification after completing the repair.

  1. «High Mount Stop Lamp Replacement»(/cadillac/elr/i-2013-2015/remont/exterior-lights/#lighting-system)
  2. «Tail Lamp Replacement»(/cadillac/elr/i-2013-2015/remont/exterior-lights/#lighting-system)
  3. «Brake Pedal Position Sensor Replacement»(/cadillac/elr/i-2013-2015/remont/exterior-lights/#lighting-system__brake-pedal-position-sensor-replacement)
  4. «Brake Pedal Position Sensor Calibration»(/cadillac/elr/i-2013-2015/remont/exterior-lights/#lighting-system__brake-pedal-position-sensor-calibration)
  5. «Control Module References»(/cadillac/elr/i-2013-2015/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM replacement, programming, and setup
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/elr/i-2013-2015/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/elr/i-2013-2015/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/elr/i-2013-2015/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
F6DR (APO/EXT LIGHTS) Fuse B+B3867 01, B3867 04, B3949 01, B3949 04B3867 01, B3867 04, B3949 01, B3949 04
F8DR (TRN SIG/LCKS) Fuse B+B3948 01, B3948 04B3948 01, B3948 04
Turn Signal Switch Signal - Left222
Tail Lamp Outage Detection Signal - Left333
Tail Lamp Outage Detection Signal - Right333
Turn Signal Switch Signal - Right222
Stop/Turn Signal Control - Left RearB3950 02B3950 01, B3950 041
Stop/Turn Signal Control - Right RearB3951 02B3951 01, B3951 041
Turn Signal Control - Left FrontB3948 02B3948 01, B3948 041
Turn Signal Control - Right FrontB3949 02B3949 01, B3949 041
Park/Turn Signal Lamp Ground - Left FrontB2585 01, B2585 04, B3948 01, B3948 04
Park/Turn Signal Lamp Ground - Right FrontB3867 01, B3867 04, B3949 01, B3949 04
Tail Lamp Ground - Left1
Tail Lamp Ground - Right1
Turn Signal/Multifunction Switch Ground2
1. Turn Signal Lamps and/or Indicators Malfunction 2. Turn Signal/Multifunction Switch Malfunction 3. 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 vehicle mode switch in the SERVICE MODE or ON positions. 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 responds to the turn signal switch input by applying a pulsating voltage to the front and rear turn signal lamps through there respective control circuits. When a turn signal request is received by the BCM, a serial data message is sent to the instrument cluster requesting the respective turn signal indicator be pulsed ON and OFF.

The tail lamp outage detection circuits are low current B+ circuits that will not illuminate a test lamp.

Schematic Reference

  1. «Exterior Lights Schematics»(/cadillac/elr/i-2013-2015/remont/exterior-lights/#lighting-system)
  2. «Body Control System Schematics»(/cadillac/elr/i-2013-2015/remont/communication-devices/#data-communication-system-schematic-wiring-diagrams)

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Vehicle in Service Mode.
  2. Verify the scan tool Right Turn Signal Switch and Left Turn Signal Switch parameters change between Active and Inactive while cycling the turn signal switch between the right and left positions. If the parameters do not change Refer to Turn Signal/Multifunction Switch Malfunction. If the parameters change
  3. Verify the left front turn signal lamp turns ON and OFF while commanding the Left Front Turn Signal Lamp ON and OFF with a scan tool. If the left front turn signal lamp does not turn ON and OFF Refer to Turn Signal Lamps Malfunction. If the left front turn signal lamp turns ON and OFF
  4. Verify the right front turn signal lamp turns ON and OFF while commanding the Right Front Turn Signal Lamp ON and OFF with a scan tool. If the right front turn signal lamp does not turn ON and OFF Refer to Turn Signal Lamps Malfunction. If the right front turn signal lamp turns ON and OFF
  5. Verify the left rear turn signal lamp turns ON and OFF while commanding the Left Rear Turn Signal/Brake Lamp ON and OFF with a scan tool. If the left rear turn signal lamp does not turn ON and OFF Refer to Turn Signal Lamps Malfunction. If the left rear turn signal lamp turns ON and OFF
  6. Verify the right rear turn signal lamp turns ON and OFF while commanding the Right Rear Turn Signal/Brake Lamp ON and OFF with a scan tool. If the right rear turn signal lamp does not turn ON and OFF Refer to Turn Signal Lamps Malfunction. If the right rear turn signal lamp turns ON and OFF
  7. Verify all front and rear turn signal lamps and the turn signal indicators on the instrument cluster flash at a normal rate while activating the left and right turn signals. If all front and rear turn signal lamps and indictors illuminate but flash in a rapid manner Refer to Tail Lamp Outage Detection Malfunction. If all front and rear turn signal lamps and indictors illuminate and flash at a normal rate
  8. Verify the left and right turn signal indicators turn ON and OFF while commanding the Instrument Cluster Gauge Sweep Test ON and OFF with a scan tool. If the left or right turn signal indictors do not turn ON and OFF Refer to Turn Signal Indicators Malfunction. If the left and right turn signal indictors turn ON and OFF
  9. All OK.

Turn Signal/Multifunction Switch Malfunction

  1. Vehicle OFF, scan tool disconnected, all doors closed, all accessories OFF, disconnect the harness connector at the S78 turn signal/multifunction switch. It may take up to 2 minutes for all vehicle systems to power down.
  2. Test for less than 10 ohms between the ground circuit terminal 6 and ground. If 10 ohms or greater Vehicle OFF. Test for less than 2 ohms in the ground circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, repair the open/high resistance in the ground connection. If less than 10 ohms
  3. Vehicle in Service Mode.
  4. Verify the scan tool Left Turn Signal Switch parameter is Inactive. If not Inactive Vehicle OFF, disconnect the X3 harness connector at the K9 body control module. Test for infinite resistance between the signal circuit terminal 5 and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance, replace the K9 body control module. If Inactive
  5. Install a 3 A fused jumper wire between the signal circuit terminal 5 and the ground circuit terminal 6.
  6. Verify the scan tool Left Turn Signal Switch parameter is Active. If not Active Vehicle OFF, disconnect the X3 harness connector at the K9 body control module, vehicle in Service Mode. Test for less than 1 V between the signal circuit terminal 5 and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V Test for less than 2 ohms in the signal circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K9 body control module. If Active
  7. Verify the scan tool Right Turn Signal Switch parameter is Inactive. If not Inactive Vehicle OFF, disconnect the X3 harness connector at the K9 body control module. Test for infinite resistance between the signal circuit terminal 4 and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance, replace the K9 body control module. If Inactive
  8. Install a 3 A fused jumper wire between the signal circuit terminal 4 and the ground circuit terminal 6.
  9. Verify the scan tool Right Turn Signal Switch parameter is Active. If not Active Vehicle OFF, disconnect the X3 harness connector at the K9 body control module, vehicle in Service Mode. Test for less than 1 V between the signal circuit terminal 4 and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V Test for less than 2 ohms in the signal circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K9 body control module. If Active
  10. Test or replace the S78 turn signal/multifunction switch.

Turn Signal Lamps Malfunction

  1. Vehicle OFF, exterior lamps OFF, disconnect the harness connector at the appropriate E4 turn signal lamp.
  2. Test for less than 5 ohms between the appropriate ground circuit terminal listed below and ground. E4N park/turn signal lamp - left terminal 1 E4Y turn signal repeater lamp - left terminal 2 E4P park/turn signal lamp - right terminal 1 E4Z turn signal repeater lamp - right terminal 2 E42L tail lamp assembly - left terminal 4 E42R tail lamp assembly - right terminal 4 If 5 ohms or greater Vehicle OFF. Test for less than 2 ohms in the ground circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, repair the open/high resistance in the ground connection. If less than 5 ohms
  3. Connect a test lamp between the appropriate control circuit terminal listed below and ground. E4N park/turn signal lamp - left terminal 3 E4Y turn signal repeater lamp - left terminal 1 E4P park/turn signal lamp - right terminal 3 E4Z turn signal repeater lamp - right terminal 1 E42L tail lamp assembly - left terminal 1 E42R tail lamp assembly - right terminal 1
  4. Verify the test lamp turns ON and OFF when commanding the appropriate Turn Signal Lamp ON and OFF with a scan tool. If the test lamp is always OFF Vehicle OFF, disconnect the appropriate harness connector listed below at the K9 body control module. X5 left turn signals X4 right turn signals Test for infinite resistance between the control circuit and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance Test for less than 2 ohms in the control circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K9 body control module. If the test lamp is always ON Vehicle OFF, disconnect the appropriate harness connector listed below at the K9 body control module, vehicle in Service Mode. X5 left turn signals X4 right turn signals Test for less than 1 V between the control circuit terminal and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V, replace the K9 body control module. If the test lamp turns ON and OFF
  5. Test or replace the appropriate E4 turn signal lamp.

Tail Lamp Outage Detection Malfunction

  1. Vehicle OFF, disconnect the harness connector at the appropriate E42 tail lamp assembly, vehicle in Service Mode.
  2. Test for B+ between the signal circuit terminal 3 and ground. If less than B+ Vehicle OFF, disconnect the appropriate harness connector listed below at the K9 body control module. X6 left tail lamp X7 right tail lamp Test for infinite resistance between the signal circuit and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance Test for less than 2 ohms in the signal circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K9 body control module. If B+
  3. Verify a test lamp does not illuminate between the signal circuit terminal 3 and ground. If the test lamp illuminates Vehicle OFF, disconnect the appropriate harness connector listed below at the K9 body control module, vehicle in Service Mode. X6 left tail lamp X7 right tail lamp Test for less than 1 V between the signal circuit terminal and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V, replace the K9 body control module. If the test lamp does not illuminate
  4. Test or replace the appropriate E42 tail lamp assembly.

Turn Signal Indicators Malfunction

  1. Vehicle in Service Mode.
  2. Verify the left and right turn signal indicators turn ON and OFF while commanding the Instrument Cluster Gauge Sweep Test ON and OFF with a scan tool. If the left or right turn signal indictors are always OFF or remain ON Replace the P16 instrument cluster. If the left and right turn signal indictors turn ON and OFF
  3. Replace the K9 body control module.

Perform the Diagnostic Repair Verification after completing the repair.

  1. «Tail Lamp Replacement»(/cadillac/elr/i-2013-2015/remont/exterior-lights/#lighting-system)
  2. «Turn Signal Switch Replacement»(/cadillac/elr/i-2013-2015/remont/steering-column-switches/#steering-wheel-and-steering-column)
  3. «Control Module References»(/cadillac/elr/i-2013-2015/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM or Instrument Cluster replacement, programming, and setup

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

Note. Do 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 calibration must be repeated.

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

Calibration Procedure

  1. Apply the parking brake.
  2. Ignition ON, engine OFF, place the transmission in the PARK position for automatic transmission or NEUTRAL position for manual transmission.
  3. Install a scan tool.
  4. Clear all DTCs before proceeding.
  5. Navigate to the Configuration/Reset Functions menu of the BCM.
  6. Select the Brake Pedal Position Sensor Learn procedure and follow the directions displayed on the screen.
  7. Navigate to the Configuration/Reset Functions menu of the ECM.
  8. Select the Learn Functions menu.
  9. Select the Brake Pedal Position Sensor Learn 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.

Removal Procedure

  1. Remove the left side instrument panel lower trim panel insulator. Refer to «Instrument Panel Lower Trim Panel Insulator Replacement - Left Side»(/cadillac/elr/i-2013-2015/remont/exteriorinterior-trim/#instrument-panel-trim-and-console-trim) .
  2. Disconnect the brake pedal position sensor electrical connector.
  3. Remove the brake pedal position sensor bolt (1).
  4. Remove the brake pedal position sensor (1) and spacer (2).

Installation Procedure

  1. Align the locating pin on the brake pedal position sensor (1) to the hole on the spacer (2).
  2. Align the locating pin on the brake pedal position sensor to the hole on the brake pedal assembly bracket.
  3. Ensure the brake pedal position sensor fork is properly located on the brake pedal pin.
  4. Install the brake pedal position sensor bolt (1) and tighten to 9 (80 lb in).
  5. Connect the brake pedal position sensor electrical connector.
  6. Install the left side instrument panel lower trim panel insulator. Refer to «Instrument Panel Lower Trim Panel Insulator Replacement - Left Side»(/cadillac/elr/i-2013-2015/remont/exteriorinterior-trim/#instrument-panel-trim-and-console-trim) .
  7. Calibrate the brake pedal position sensor. Refer to «Brake Pedal Position Sensor Calibration»(/cadillac/elr/i-2013-2015/remont/exterior-lights/#lighting-system__brake-pedal-position-sensor-calibration) .

Scheme 13

Scheme 13: Interior Lamp Switch Replacement (Reading Lamp)
Scheme 13: Interior Lamp Switch Replacement (Reading Lamp)
CalloutComponent Name
Preliminary Procedure Remove the center reading and courtesy lamp. Refer to Center Reading and Courtesy Lamp Replacement .
1Interior Lamp Switch Procedure Release the tabs and remove the switch.

Interior Lamp Switch Replacement (Reading Lamp)

Scheme 14

Scheme 14: Interior Lamp Switch Replacement (Dimmer)
Scheme 14: Interior Lamp Switch Replacement (Dimmer)
CalloutComponent Name
Preliminary Procedure Remove the instrument panel knee bolster. Refer to Instrument Panel Knee Bolster Replacement .
1Interior Lamp Switch Procedure Release tabs on switch to remove from the bezel.

Interior Lamp Switch Replacement (Dimmer)

Scheme 15

Scheme 15: Hazard Warning Switch Replacement
Scheme 15: Hazard Warning Switch Replacement
CalloutComponent Name
Preliminary Procedure Remove the instrument panel accessory bracket. Refer to Instrument Panel Accessory Bracket Replacement .
1Hazard Warning Switch Procedure Using the appropriate tool, depress the tabs on switch to remove from the bracket.

Hazard Warning Switch Replacement

Scheme 16

Scheme 16: Dome and Reading Lamp Switch Replacement
Scheme 16: Dome and Reading Lamp Switch Replacement
CalloutComponent Name
Preliminary Procedure Remove the roof console. Refer to Roof Console Replacement .
1Dome and Reading Lamp Switch Procedure Release the tabs and remove the switch.

Dome and Reading Lamp Switch Replacement

Scheme 17

Scheme 17: Center Reading Lamp Replacement
Scheme 17: Center Reading Lamp Replacement
CalloutComponent Name
1Center Reading Lamp Procedure Grasp the front of the right and left sides of the center reading lamp assembly and pull downward using equal force on each side in order to release the two retainer clips securing the lamp assembly to the headlining assembly. Pivot the assembly rearwards to release the rear two retainer clips. Disconnect the electrical connections.

Center Reading Lamp Replacement

Scheme 18

Scheme 18: Center Courtesy Lamp Replacement
Scheme 18: Center Courtesy Lamp Replacement
CalloutComponent Name
Preliminary Procedure Remove the garage door opener transmitter pushbutton trim plate. Refer to Garage Door Opener Transmitter Pushbutton Trim Plate Replacement .
1Center Courtesy Lamp Procedure Release the tabs and remove the lamp.

Center Courtesy Lamp Replacement

Scheme 19

Scheme 19: Center Reading and Courtesy Lamp Replacement
Scheme 19: Center Reading and Courtesy Lamp Replacement
CalloutComponent Name
Preliminary Procedure Remove the roof console. Refer to Roof Console Replacement .
1Center Reading and Courtesy Lamp Fasteners (Qty: 3) CAUTION: Refer to Fastener Caution .
2Center Reading and Courtesy Lamp
CAUTION
Refer to Fastener Caution .

Center Reading and Courtesy Lamp Replacement

Scheme 20

Scheme 20: Front Floor Courtesy Lamp Replacement (Left Side)
Scheme 20: Front Floor Courtesy Lamp Replacement (Left Side)
CalloutComponent Name
Preliminary Procedure Remove the instrument panel lower trim panel insulator - left side. Refer to Instrument Panel Lower Trim Panel Insulator Replacement - Left Side .
1Front Floor Courtesy Lamp Procedure Using the appropriate tool, release the tabs on lamp to remove from insulator panel.

Front Floor Courtesy Lamp Replacement (Left Side)

Scheme 21

Scheme 21: Front Floor Courtesy Lamp Replacement (Right Side)
Scheme 21: Front Floor Courtesy Lamp Replacement (Right Side)
CalloutComponent Name
Preliminary Procedure Remove the instrument panel lower trim panel insulator - right side. Refer to Instrument Panel Lower Trim Panel Insulator Replacement - Right Side .
1Front Floor Courtesy Lamp Procedure Using the appropriate tool, release the tabs on lamp to remove from insulator panel.

Front Floor Courtesy Lamp Replacement (Right Side)

Scheme 22

Scheme 22: Front Floor Console Compartment Lamp Replacement
Scheme 22: Front Floor Console Compartment Lamp Replacement
CalloutComponent Name
Preliminary Procedure Remove the front floor console compartment. Refer to Front Floor Console Compartment Replacement .
1Front Floor Console Compartment Lamp Procedure Use a plastic flat bladed trim tool in order to release the lamp assembly from the compartment. Disconnect the electrical connection.

Front Floor Console Compartment Lamp Replacement

Scheme 23

Scheme 23: Front Floor Console Compartment Lamp Switch Replacement
Scheme 23: Front Floor Console Compartment Lamp Switch Replacement
CalloutComponent Name
Preliminary Procedure Remove the front floor console compartment. Refer to Front Floor Console Compartment Replacement .
1Front Floor Console Compartment Lamp Switch Procedure Use a plastic flat bladed trim tool in order to release the lamp switch from the compartment. Unclip the lamp assembly from the compartment. Disconnect the electrical from the compartment lamp.

Front Floor Console Compartment Lamp Switch Replacement

Scheme 24

Scheme 24: Front Side Door Inside Handle Illumination Lamp Replacement
Scheme 24: Front Side Door Inside Handle Illumination Lamp Replacement
CalloutComponent Name
Preliminary Procedure Remove the front side door trim. Refer to Front Side Door Trim Replacement .
1Front Side Door Inside Handle Illumination Lamp Procedure Disconnect the electrical connectors. Unsnap lamp assembly from trim panel tabs.

Front Side Door Inside Handle Illumination Lamp Replacement

Scheme 25

Scheme 25: Front Side Door Trim Flexible Light Tube Replacement
Scheme 25: Front Side Door Trim Flexible Light Tube Replacement
CalloutComponent Name
Preliminary Procedure Remove the front side door trim. Refer to Front Side Door Trim Replacement .
1Front Side Door Trim Flexible Light Tube Procedure Disconnect the electrical connectors. Unlatch the lamp assembly from the back of the trim panel. Unsnap lamp assembly from tabs in the front of the trim panel.

Front Side Door Trim Flexible Light Tube Replacement

Scheme 26

Scheme 26: Front Side Door Courtesy Lamp Replacement
Scheme 26: Front Side Door Courtesy Lamp Replacement
CalloutComponent Name
Preliminary Procedure Remove the front side door trim. Refer to Front Side Door Trim Replacement .
1Front Side Door Courtesy Lamp Procedure Disconnect the electrical connector. Unsnap lamp assembly from bracket tabs.

Front Side Door Courtesy Lamp Replacement

Scheme 27

Scheme 27: Instrument Panel Light Conductor Lamp Replacement (Left Side)
Scheme 27: Instrument Panel Light Conductor Lamp Replacement (Left Side)
CalloutComponent Name
Preliminary Procedure Remove the instrument panel trim plate applique - left side. Refer to Instrument Panel Trim Plate Applique Replacement - Left Side .
1Instrument Panel Light Conductor Lamp Procedure Disconnect the electrical connector. Unsnap lamp assembly from the retainer.

Instrument Panel Light Conductor Lamp Replacement (Left Side)

Scheme 28

Scheme 28: Instrument Panel Light Conductor Lamp Replacement (Center)
Scheme 28: Instrument Panel Light Conductor Lamp Replacement (Center)
CalloutComponent Name
Preliminary Procedure Remove the instrument panel lower trim plate applique. Refer to Instrument Panel Lower Trim Plate Applique Replacement . Remove the instrument panel lower center trim plate applique. Refer to Instrument Panel Lower Center Trim Plate Applique Replacement .
1Instrument Panel Light Conductor Lamp Procedure Disconnect the electrical connector. Unsnap lamp assembly from retainer.

Instrument Panel Light Conductor Lamp Replacement (Center)

Scheme 29

Scheme 29: Instrument Panel Light Conductor Lamp Replacement (Right Side)
Scheme 29: Instrument Panel Light Conductor Lamp Replacement (Right Side)
CalloutComponent Name
Preliminary Procedure Remove the instrument panel compartment. Refer to Instrument Panel Compartment Replacement .
1Instrument Panel Light Conductor Lamp Procedure Disconnect the electrical connector. Unsnap lamp assembly from the compartment.

Instrument Panel Light Conductor Lamp Replacement (Right Side)

Scheme 30

Scheme 30: Instrument Panel Compartment Lamp Replacement
Scheme 30: Instrument Panel Compartment Lamp Replacement
CalloutComponent Name
Preliminary Procedure Remove the instrument panel compartment. Refer to Instrument Panel Compartment Replacement .
1Instrument Panel Compartment Lamp Procedure Disconnect the electrical connector. Using the appropriate tool depress tabs to release.

Instrument Panel Compartment Lamp Replacement

Scheme 31

Scheme 31: Instrument Panel Compartment Lamp Switch Replacement
Scheme 31: Instrument Panel Compartment Lamp Switch Replacement
CalloutComponent Name
Preliminary Procedure Remove the instrument panel compartment. Refer to Instrument Panel Compartment Replacement .
1Instrument Panel Compartment Lamp Switch Procedure Disconnect the electrical connector. Depress the tabs on the lamp switch to remove.

Instrument Panel Compartment Lamp Switch Replacement

Scheme 32

Scheme 32: Outside Rearview Mirror Turn Signal Lamp Replacement
Scheme 32: Outside Rearview Mirror Turn Signal Lamp Replacement
CalloutComponent Name
Preliminary Procedure Remove the outside rearview mirror housing lower cover. Refer to OUTSIDE REARVIEW MIRROR REPLACEMENT .
1Outside Rearview Mirror Turn Signal Lamp Procedure Separate the outside rearview mirror turn signal lamp from the mirror lower housing.

Outside Rearview Mirror Turn Signal Lamp Replacement

Scheme 33

Scheme 33: Headlamp Replacement
Scheme 33: Headlamp Replacement
CalloutComponent Name
Preliminary Procedure Remove the front bumper fascia. Refer to Front Bumper Fascia Removal and Installation .
1Headlamp Bolt (Qty: 4) CAUTION: Refer to Fastener Caution . Tighten 2.5 N.m (22 lb in)
2Headlamp Procedure Disconnect the electrical wiring harness and remove the headlamp. Aim the headlamp after replacement. Refer to Headlamp Aiming .
CAUTION
Refer to Fastener Caution .

Headlamp Replacement

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.

Scheme 34

Scheme 34: Daytime Running Lamp Replacement
Scheme 34: Daytime Running Lamp Replacement
CalloutComponent Name
Preliminary Procedure Remove the front wheelhouse liner. Refer to Front Wheelhouse Liner Replacement .
1Daytime Running Lamp Screw (Qty: 4) CAUTION: Refer to Fastener Caution . Tighten 2.5 N.m (22 lb in)
2Daytime Running Lamp Procedure Disconnect electrical connector. Remove daytime running lamp from front lower grille.
CAUTION
Refer to Fastener Caution .

Daytime Running Lamp Replacement

Scheme 35

Scheme 35: Front Side Marker Lamp Replacement
Scheme 35: Front Side Marker Lamp Replacement
CalloutComponent Name
Preliminary Procedure Remove the front wheelhouse liner. Refer to Front Wheelhouse Liner Replacement .
1Front Side Marker Lamp Procedure Disconnect electrical connector. Use a flat bladed tool to compress the retainer on the top of the front side marker lamp and remove from the front bumper fascia.

Front Side Marker Lamp Replacement

Scheme 36

Scheme 36: Rear Reflector Replacement
Scheme 36: Rear Reflector Replacement
CalloutComponent Name
Preliminary Procedure1 Remove the underbody rear air deflector. Refer to Underbody Rear Air Deflector Replacement .
1Screw (Qty: 2) CAUTION: Refer to Fastener Caution .
2Rear Bumper Fascia Reflector Procedure Press on the retainer tabs in order to remove the reflector from the rear bumper lower fascia.
CAUTION
Refer to Fastener Caution .

Rear Reflector Replacement

Scheme 37

Scheme 37: High Mount Stop Lamp Replacement
Scheme 37: High Mount Stop Lamp Replacement
CalloutComponent Name
Preliminary Procedure Remove the rear compartment lid inner panel trim. Refer to Rear Compartment Lid Inner Panel Trim Replacement .
1High Mount Stop Lamp Nut (Qty: 4) CAUTION: Refer to Fastener Caution . Tighten 4.7 N.m (42 lb in)
2W-clip (Qty: 2)
2High Mount Stop Lamp Procedure Disconnect the electrical connector. Using a heat gun from inside the rear compartment lid in a circular motion, in order to assist in the adhesive tape removal. Compress the tabs to release the 2 W-clips. Remove the high mount stop lamp from the vehicle. Clean the area with a 50/50 mixture by volume of isopropyl alcohol and clean drinkable water to remove any left over adhesive residue. Dry the area thoroughly with a clean dry cotton cloth before applying the new high mount stop lamp. Pull off the adhesive release tape and set the high mount stop lamp into position. Use a dry cotton cloth to wet out the entire surface of the high mount stop lamp.
CAUTION
Refer to Fastener Caution .

High Mount Stop Lamp Replacement

Scheme 38

Scheme 38: Backup Lamp Replacement
Scheme 38: Backup Lamp Replacement
CalloutComponent Name
Preliminary Procedure Remove rear bumper fascia. Refer to Rear Bumper Fascia Removal and Installation . Disconnect the backup lamp bulb sockets.
1Backup Lamp Screw (Qty: 3) CAUTION: Refer to Fastener Caution . Tighten 2.5 N.m (22 lb in)
2Backup Lamp Procedure Remove backup lamp from rear bumper fascia.
CAUTION
Refer to Fastener Caution .

Backup Lamp Replacement

Scheme 39

Scheme 39: Backup Lamp Bulb Replacement
Scheme 39: Backup Lamp Bulb Replacement
CalloutComponent Name
Preliminary Procedure Remove the underbody rear air deflector. Refer to, Underbody Rear Air Deflector Replacement .
1Rear Backup Lamp Bulb Socket (Qty:2) Procedure Rotate the rear backup lamp bulb socket counterclockwise and remove from rear backup lamp.
2Rear Backup Lamp Bulb (Qty:2) Procedure Pull the backup lamp blub straight out from backup lamp socket.

Backup Lamp Bulb Replacement

Scheme 40

Scheme 40: Rear License Plate Lamp Replacement
Scheme 40: Rear License Plate Lamp Replacement
CalloutComponent Name
1Rear License Plate Lamp Procedure Use a flat bladed tool to compress the retainer on the outboard end of the rear license plate lamp and release the rear license plate lamp from the rear compartment lid. Disconnect electrical connector.

Rear License Plate Lamp Replacement

Scheme 41

Scheme 41: Rear License Plate Lamp Bulb Replacement
Scheme 41: Rear License Plate Lamp Bulb Replacement
CalloutComponent Name
Preliminary Procedure Remove the rear license plate lamp. Refer to Rear License Plate Lamp Replacement .
1Rear License Plate Lamp Bulb Procedure Pull rear license plate lamp bulb straight out from rear license plate lamp bulb socket.

Rear License Plate Lamp Bulb Replacement

Scheme 42

Scheme 42: Tail Lamp Replacement
Scheme 42: Tail Lamp Replacement
CalloutComponent Name
Preliminary Procedures Remove rear bumper fascia. Refer to Rear Bumper Fascia Removal and Installation . Remove the rear compartment side trim panel on the side to be serviced. Refer to Rear Compartment Side Trim Replacement - Left Side , or Rear Compartment Side Trim Replacement - Right Side . Disengage the rear compartment lid weatherstrip from the tail lamp area.
1Tail Lamp Assembly Nut (Qty: 3) CAUTION: Refer to Fastener Caution . Tighten 4.7 N.m (42 lb in)
2Tail Lamp Assembly Procedure Depress the locking tab, downward on top of the electrical connector and pull to disconnect the electrical connector from the tail lamp assembly. Pull the lamp rearward in order to disconnect the three locator pins from the bodyside tail lamp pocket. Remove the tail lamp assembly.
CAUTION
Refer to Fastener Caution .

Tail Lamp Replacement

Scheme 43

Scheme 43: Rear Compartment Courtesy Lamp Replacement
Scheme 43: Rear Compartment Courtesy Lamp Replacement
CalloutComponent Name
Preliminary Procedure Remove the rear window panel trim. Refer to Rear Window Panel Trim Replacement .
1Rear Compartment Courtesy Lamp Procedure Use the appropriate tool to depress the tabs on lamp and remove. Disconnect the electrical connection.

Rear Compartment Courtesy Lamp Replacement

Exterior Lamps

The exterior lighting system consist of the following lamps if equipped

  1. Automatic high beam assist
  2. Backup lamps
  3. Hazard warning lamps
  4. Headlamps
  5. Park, tail and license lamps
  6. Repeater lamps
  7. Rear fog lamps
  8. Stop lamps
  9. Turn signal lamps

Low Beam Headlamps

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
  3. When the headlamp switch is placed in the AUTO position, with the windshield wipers ON in daylight conditions, after a 6 second delay

The BCM will also command the low beam headlamps ON during daylight conditions when the following conditions are met

  1. Headlamp switch in the AUTO position
  2. Windshield wipers ON
  3. Vehicle in any gear but PARK

The body control module (BCM) monitors three signal circuits from the headlamp switch. When the headlamp switch is in the AUTO position, all three signal circuits are open. When placed in the AUTO position, the BCM monitors inputs from the ambient light sensor to determine if headlamps are required or if daytime running lamps will be activated based on outside lighting conditions. When the headlamp switch is placed in the OFF position, the headlamp switch headlamps OFF signal circuit is grounded, indicating to the BCM that the exterior lamps should be turned OFF. With the headlamp switch in the PARK position, the headlamp switch park lamps ON signal circuit is grounded, indicating that the park lamps have been requested. When the headlamp switch is placed in the HEADLAMP position, both the headlamp switch park lamps ON signal circuit and the headlamp switch headlamps ON signal circuit are grounded. The BCM responds to the inputs by illuminating the park lamps and headlamps. When the low beam headlamps are requested, the BCM applies B+ to both low beam headlamp control circuits illuminating the low beam headlamps.

When the BCM commands the low beam headlamps ON, the operator will notice the interior backlighting for the instrument cluster and the various other switches dim to the level of brightness selected by the instrument panel dimmer switch.

High Beam Headlamps

When the low beam headlamps are ON and the turn signal/multifunction switch is placed in the high beam position, ground is applied to the BCM through the high beam signal circuit. The BCM responds to the high beam request by applying ground to the 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 left and right high beam fuses to the high beam control circuits and on to the left and right high beam headlamps illuminating the high beam headlamps.

Automatic High Beam Assist (AHBA)

The automatic high beam assist (AHBA) system operates the high beam headlamps ON and OFF automatically when the system is activated and certain conditions are met. The AHBA system consists of a front camera module that detects light and is able to identify approaching vehicles on an even, straight road at a distance of greater than 0.4 km (0.25 mi). The front camera module analyzes light color, intensity, and movement. The AHBA system will turn OFF the high beam headlamps when approaching vehicle headlamps or preceding vehicle taillights are detected by the front camera module. AHBA can be deactivated when the headlamp dimmer switch is moved from the neutral position to the high beam or flash to pass (FTP) positions. AHBA can be reactivated by operating the high beam select switch from the neutral position to the high beam position twice within 2 seconds.

The following are conditions that the AHBA system will turn the high beams off during operation

  1. Approaching traffic
  2. Preceding traffic
  3. Ambient light level too high due to towns or twilight situations
  4. Vehicle speed less than 25 mph (40 km/h)
  5. Delay

Note. AHBA may not operate properly if any of the following conditions exist

  1. Approaching and preceding vehicles lamps are undetectable due to dirt, snow, road spray, smoke, fog, or any other airborne conditions.
  2. The front camera module is covered with ice, dirt, snow, haze, or is obstructed.
  3. The vehicle is being driven on winding or hilly road conditions which would make any on coming vehicle headlamps undetectable by the AHBA.

AHBA System Activation

  1. Vehicle ON
  2. Headlamp switch placed in the AUTO position
  3. Select Auto High Beam ON in the vehicles customization menu
  4. Headlamp dimmer switch must be in the neutral position
  5. Outside lighting conditions must be dark
  6. AHBA is deactivated automatically when the front or rear fog lamps are turned ON

AHBA System Deactivation

  1. Manually operating the headlamp dimmer switch from neutral to high beam position
  2. Select Auto High Beam OFF in the vehicles customization menu

AHBA System Indicator

The status of the AHBA system is shown by a green indicator located on the instrument panel cluster. When AHBA is active, the indicator will be illuminated continuously. If the operator deactivates the AHBA system, the indicator will turn off.

Daytime Running Lamps

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

  1. The vehicle mode switch 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 low and high 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 body control module (BCM) provides a 5-volt reference signal to the ambient light sensor and the HVAC control module provides a low reference ground. The BCM monitors the ambient light sensor signal circuit to determine if outside lighting conditions are correct for either daytime running lights or automatic lamp control when the headlamp switch is in the AUTO position. In daylight conditions the BCM will command the designated daytime running lights 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 daytime running lights operation.

Flash to Pass

When the low beam headlamps are on and the turn signal/multi-function switch is momentarily placed in the flash to pass position, ground is applied to the turn signal/multi-function switch. The turn signal/multifunction switch applies ground to the BCM through the flash to pass 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.

Hazard Lamps

The hazard flashers may be activated in any power mode. The hazard switch signal circuit is momentarily grounded when the hazard switch is pressed. The body control module (BCM) responds to the hazard switch signal input by supplying 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 requesting both turn signal indicators to be cycled ON and OFF.

The instrument panel dimmer switch controls the brightness of the interior backlighting components. When the instrument panel dimmer switch is placed in a desired brightness position, the body control module (BCM) receives a signal from the instrument panel dimmer switch and responds by applying a pulse width modulated (PWM) voltage to the hazard switch light emitting diode (LED) backlighting control circuit illuminating the LED to the desired level of brightness.

Park, Tail and License Lamps

The park lamps, tail lamps and license plate lights are turned ON when the headlamp switch is placed in the PARK LIGHT or LOW BEAM position or anytime the headlights are requested. When the BCM receives a request from the headlamp switch to turn ON the park lamps the BCM a sends out a PWM signal, which illuminates the park lamps, tail lamps and license plate lights.

Stop Lamps

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.

The brake pedal position (BPP) sensor is used to sense the action of the driver application of the brake pedal. The BPP 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 BPP sensor. When the variable signal reaches a voltage threshold indicating the brakes have been applied, the BCM will apply battery voltage to the left and right stop lamp control circuits as well as the center high mounted stop lamp control circuit illuminating the left and right stop lamps and the center high mounted stop lamp.

Turn Signal Lamps

Ground is applied at all times to the turn signal/multi-function switch. The turn signal lamps may only be activated with the vehicle ON/OFF switch in the Service Mode or ON position. When the turn signal/multi-function switch is placed in either the TURN RIGHT or TURN LEFT position, ground is applied to the 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 their respective voltage supply circuits. When a turn signal request is received by the BCM, a serial data message is sent to the instrument cluster requesting the respective turn signal indicator be pulsed ON and OFF.

Repeater Lamps

The repeater lamps are 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.

Backup Lamps

With the engine ON and the transmission 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 control circuit illuminating the backup lamps. 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 lamps control circuit. The vehicle must be ON for the backup lamps to operate.

Battery Run Down Protection/Inadvertent Power

To provide battery run down protection, the exterior lamps will be deactivated automatically under certain conditions. The BCM monitors the state of the headlamp switch. If the park or headlamp switch is ON when the vehicle mode switch is placed in either the CRANK or RUN position and then placed in the OFF position, the BCM initiates a 10 min timer. At the end of the 10 min, the BCM will turn off the control power output to the park lamp controls as well as the 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 vehicle mode switch was turned OFF.

Interior Lamps

The interior lamps consist of 2 groups, those which can dim from the instrument panel cluster lamps dimmer switch and those that can not dim.

Courtesy/Illuminated Entry Lamps

The following lamps may be manually turned ON by placing the interior lamp switch in the ON position, or by opening a door while the switch is in the AUTOMATIC LIGHT position.

  1. The dome lamp
  2. The liftgate lamps
  3. Courtesy lamps

The courtesy lamp supply voltage circuit of the body control module (BCM) supplies battery positive voltage to the dome lamp, the liftgate lamps and courtesy lamps. When any door is opened, the door jamb switch contacts close providing a door open input to the BCM. The BCM then provides a B+ to the interior lamps with the switch in the AUTO position. The interior lamps receive a ground when the switch is in the ON position.

Note. If the liftgate is opened after all the modules go to sleep, the dome light will not come on. The liftgate ajar switch input to the BCM will not wake up the BCM once it has gone to sleep, so the dome light will not come on. Once the BCM gets an input to wake it up, from remote keyless entry or a door handle, the dome light will turn on when the liftgate is opened.

If the driver inadvertently leaves any interior lamp ON, the BCM will turn it OFF after a 20 min time-out.

The courtesy lamps will turn OFF immediately if the vehicle ON/OFF switch is turned to the ON position or approximately 20 s after all doors are closed.

Keyless Entry Interior Illumination

When the BCM receives a door unlock command from the remote keyless entry transmitter, the BCM will flash the park lamps several times, illuminate the courtesy and park lamps, and illuminate the low beam headlamps at low intensity. The lamps will remain on until the vehicle ON/OFF switch is turned from the OFF position, a keyless entry transmitter door lock command is received, or after an approximate 20 s delay.

Interior Lamps Dimming

This group includes lamps which may dim. This group may use a combination of vacuum fluorescent illumination, LEDs and incandescent lamps.

  1. HVAC control module, head assembly
  2. Rear HVAC control module, head assembly
  3. Radio
  4. Rear seat audio
  5. The instrument panel cluster
  6. The PRNDL lamp, with the exception of the current gear select position
  7. Power window switches
  8. Various switches

When the vehicle ON/OFF switch is turned to the ON position, the vacuum fluorescent display, radio, turns ON at maximum brightness. When the park lamps are ON, all incandescent back lighting turn ON at the dimming level indicated by the instrument panel dimmer switch. At the same time all fluorescent display displays dim to match the indicated dimming level. When the headlamp switch is placed in the PARK position, the park lamp supply voltage circuit provides an input to the BCM. The BCM then supplies voltage to the instrument panel dimmer switch through the dimming control circuit. The setting of the instrument panel dimmer switch determines the amount of voltage that the instrument panel dimmer switch supplies to the BCM through the instrument panel dimming lamps low reference circuit. The BCM then sends a PWM voltage to all the interior lamps. All the fluorescent display and incandescent back lighting lamps are provided a specific voltage and are then grounded. When the headlight switch is turned to the park lamp or headlamp position, all incandescent back lighting turn ON at the dimming level indicated by the instrument panel dimmer switch. When the instrument panel dimmer switch is moved from MIN to MAX, all fluorescent display displays, as well as all incandescent back lighting respond from minimum intensity to maximum brightness in response to the instrument panel dimmer switch.

Inadvertent Power

The BCM used in this vehicle controls the lighting system through circuits that enable the interior lamps. The BCM opens these enabling circuits shortly after the vehicle ON/OFF switch is turned OFF with no lamp switch activity. If the vehicle ON/OFF switch is turned to any position other than OFF, or if a lamp switch is activated during this period, the timer will reset itself.

See also:
• Diagnostic System Check - Vehicle
• Strategy Based Diagnosis
• Diagnostic Procedure Instructions
• COMPONENT CONNECTOR END VIEWS - INDEX
• Circuit Testing
• Connector Repairs
• Testing for Intermittent Conditions and Poor Connections
• Wiring Repairs
• Control Module References
• Diagnostic Repair Verification
• Ignition and Start Switch Replacement
• Body Control System Schematics
• Sunshade Replacement
• Turn Signal Switch Replacement
• Outside Rearview Mirror Remote Control Switch Replacement
• Radio Control Assembly Replacement
• Garage Door Opener Transmitter Pushbutton Replacement
• Parking Brake Switch Replacement
• Fuel Tank Filler Door Lock Release Switch Replacement
• Sun Load Temperature and Headlamp Automatic Control Ambient Light Sensor Replacement
• Checking Aftermarket Accessories
• SIR Schematics
• Instrument Panel Lower Trim Panel Insulator Replacement - Left Side
• Fastener Caution
• Front Bumper Fascia Removal and Installation
• Front Wheelhouse Liner Replacement
• DTC B096F
• Brake Pedal Position Sensor Calibration
• Brake Pedal Position Sensor Replacement