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Contents Wiring diagrams Section: Exterior Lights All sections

Lighting System Cadillac Escalade GMT900

Exterior Lights 79 illustrations ~36097 words

Fastener Tightening Specifications

ApplicationSpecification
MetricEnglish
Center High-Mounted Stop Lamp Mounting Screws2 N.m18 lb in
Headlamp Ballast Screws2 N.m18 lb in
Headlamp Mounting Screws6 N.m53 lb in
License Plate Lamp Screws2 N.m18 lb in
Power Vacuum Brake Booster Pushrod Retaining Bolt10 N.m89 lb in
Rear Tail/Turn Signal Lamp Assembly Screws2 N.m18 lb in

Scheme 1

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

Scheme 2

Scheme 2
Scheme 2

Scheme 3

Scheme 3
Scheme 3

Scheme 4

Scheme 4
Scheme 4

Scheme 5

Scheme 5
Scheme 5

Scheme 6

Scheme 6: Fog Lights Schematics
Scheme 6: Fog Lights Schematics

Scheme 7

Scheme 7: Exterior Lights Schematics
Scheme 7: Exterior Lights Schematics

Scheme 8

Scheme 8
Scheme 8

Scheme 9

Scheme 9
Scheme 9

Scheme 10

Scheme 10
Scheme 10

Scheme 11

Scheme 11
Scheme 11

Scheme 12

Scheme 12
Scheme 12

Scheme 13

Scheme 13
Scheme 13

Scheme 14

Scheme 14
Scheme 14

Scheme 15

Scheme 15
Scheme 15

Scheme 16

Scheme 16
Scheme 16

Scheme 17

Scheme 17
Scheme 17

Scheme 18

Scheme 18
Scheme 18

Scheme 19

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

Scheme 20

Scheme 20
Scheme 20

Scheme 21

Scheme 21
Scheme 21

Scheme 22

Scheme 22: Interior Lights Dimming Schematics
Scheme 22: Interior Lights Dimming Schematics

Scheme 23

Scheme 23
Scheme 23

Scheme 24

Scheme 24
Scheme 24

Scheme 25

Scheme 25
Scheme 25

DIAGNOSTIC CODE INDEX

DTCDescription
DTC B1395B1395 03: Device Voltage Reference Output 1 Circuit Voltage Below Threshold B1395 07: Device Voltage Reference Output 1 Circuit Voltage Above Threshold
DTC B2530B2530 00: Front Fog Lamps Control Circuit
DTC B2540B2540 02: Rear Fog Lamp Control Circuit Short to Ground B2540 05: Rear Fog Lamp Control Circuit Short to Battery or Open
DTC B2545B2545 00: Backup Lamps Circuit
DTC B2555B2555 01: Passenger Compartment Lamp Control Circuit Short to Battery B2555 02: Passenger Compartment Lamp Control Circuit Short to Ground
DTC B25752575 00: Headlamp Control Circuit
DTC B257AB257A 00: Headlamp Switch Input Signals Mismatch
DTC B2580B2580 00: Headlamp High Beam Control Circuit
DTC B2585B2585 00: Park Lamp Control Circuit
DTC B2600 (With X88, Z75, and Z88)B2600 00: Daytime Running Lamp Control Circuit
DTC B2600 (With T4Q)B2600 00: Daytime Running Lamp Control Circuit
DTC B2610B2610 00: Passenger Compartment Dimming 1 Circuit
DTC B2615B2615 00: Passenger Compartment Dimming 2 Circuit
DTC B2625B2625 00: Display Dimming Pulse Width Modulation (PWM) Output Circuit
DTC B2645B2645 03: Ambient Light Sensor Circuit Voltage Below Threshold B2645 07: Ambient Light Sensor Circuit Voltage Above Threshold
DTC B2652B2652 00: Passenger Compartment Dimming 3 Circuit
DTC B3445B3445 00: Stop Lamp Circuit
DTC B3588B3588 02: Rear Fog Lamp Switch Circuit Short to Ground
DTC B3600B3600 03: Passenger Compartment Dimming Request Signal Circuit Voltage Below Threshold B3600 07: Passenger Compartment Dimming Request Signal Circuit Voltage Above Threshold
DTC B3884B3884 00: Center High Mounted Stop Lamp (CHMSL) Circuit
DTC B3891B3891 02: Trailer Fog Lamps Circuit Short to Ground B3891 05: Trailer Fog Lamps Circuit Short to Battery or Open
DTC C0277, C0297, or C0890C0277 06: Brake Pedal Position Sensor Circuit Short to Ground or Open C0277 07: Brake Pedal Position Sensor Circuit Voltage Above Threshold C0277 09: Brake Pedal Position Sensor Circuit Rate of Change Above Threshold C0277 4B: Brake Pedal Position Sensor Calibration Not Learned C0297 00: Brake Applied Output Circuit C0890 03: Device Voltage Reference Output 3 Circuit Voltage Below Threshold C0890 07: Device Voltage Reference Output 3 Circuit Voltage Above Threshold

DIAGNOSTIC CODE INDEX

Diagnostic Instructions

  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

Diagnostic Fault Information

CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Dome/Reading Lamp Supply Voltage11
Dome/Reading Lamp ControlB2615 00B2615 00
Stop Lamp Switch SignalB1395 03, B3600 03
I/P Dimming Voltage ReferenceB1395 03, B3600 03B1395 03, B2652 00, B3600 03B1395 07
Courtesy Lamp Voltage ReferenceB2615 00, B2615 02B2615 00, B2615 04B2615 00, B2615 01
LED Dimming Voltage ReferenceB2610 00, B2610 02B2610 00, B2610 04B2610 00, B2610 01
LED Indicator Dimming Volage ReferenceB2625 00B2625 00B2625 00
Dome Lamp Switch Signal222
Left Front Door Open Switch Signal333
Left Rear Door Open Switch Signal444
Right Front Door Open Switch Signal333
Right Rear Door Open Switch Signal444
Exterior Lamps Illumination Supply Voltage555
Inadvertent Power Control555
I/P Lamps Dimming ControlB2652 00B2652 00B2652 00
Dome/Reading Lamp Low Control - Driver Door1
Dome/Reading Lamp Low Control - Passenger Door1
Exterior Lamps Low Reference5
I/P Dimmer Switch Ground2
LH Vanity Mirror Courtesy Lamp Ground1
Overhead Console Courtesy Lamp Ground1
Rear Dome Lamp Ground1
RH Vanity Mirror Courtesy Lamp Ground1
1. Courtesy Lamps Malfunction 2. Dome Lamp Switch Malfunction 3. Door Open Switch Malfunction - Front 4. Door Open Switch Malfunction - Rear 5. Exterior Lamps Malfunction

Circuit/System Description

Voltage for the interior backlighting components and stop lamp switch activation signal is supplied from the body control module (BCM). The BCM applies a voltage reference through the instrument panel (I/P) dimming voltage reference circuit to the interior lamp dimming switch, which is part of the headlamp switch. When the dimming switch is placed in the desired position, the dimmed voltage setting is applied from the interior lamp dimming switch through the I/P dimming control circuit to the BCM. The BCM then applies the dimmed voltage to the I/P lamps supply voltage circuit and they dim to the correct level.

The stop lamp switch is also supplied voltage on the same circuit for a stop lamp OFF signal to the BCM. When the stop lamp switch is activated the voltage signal circuit to the BCM is opened prompting the BCM to illuminate the stop lamps.

Conditions for Running the DTC

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

B1395 03

The BCM detects a voltage that is lower than 0.33 V on the I/P dimming voltage reference circuit.

B1395 07

The BCM detects a voltage that is greater than 4.97 V on I/P dimming voltage reference circuit.

Action Taken When the DTC Sets

  1. The I/P lamps are dim or not illuminated.
  2. The I/P lamps will not dim.
  3. The stop lamps are always ON.

Conditions for Clearing the DTC

  1. The conditions for setting the DTC are no longer present.
  2. A history DTC clears after 100 malfunction-free ignition cycles.
  3. The BCM receives the clear code command from the scan tool.

Reference Information

Schematic Reference

  1. «Interior Lights Dimming Schematics»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system)
  2. «Exterior Lights Schematics»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system)

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Testing

  1. Ignition OFF, disconnect the harness connector at the headlamp and panel dimmer switch.
  2. Ignition OFF, verify that a test lamp illuminates between the ground circuit terminal 8 and B+. If the test lamp does not illuminate, test the ground circuit for an open/high resistance.
  3. Ignition ON, verify the scan tool Dimming Control Signal parameter is less than 0.1 V. If greater than the specified range, test the signal circuit terminal 13 for a short to voltage. If the circuit tests normal, replace the BCM.
  4. Ignition ON, test for 12 V between the I/P dimming voltage reference circuit terminal 15 and ground. If less than the specified value, test the voltage reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM.
  5. Install a 3 A fused jumper wire between the signal circuit terminal 13 and the voltage reference circuit terminal 15. Verify the scan tool BCM Dimming Control Signal parameter is greater than 2.6 V. If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM.
  6. If all circuits test normal, test or replace the headlamp and panel dimmer switch.

Repair Procedures

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Headlamp Switch Replacement (Cadillac)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) or «Headlamp Switch Replacement (Except Cadillac)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system)
  2. «Control Module References»(/cadillac/escalade/gmt900-2006-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM replacement, setup, and programming
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Front Fog Lamp Switch Signal222
Front Fog Lamp Relay Control11B2530 00
Front Fog Lamp Control111
Fog Lamp - LF Ground1
Fog Lamp - RF Ground1
Fog Lamp Switch Ground2
1. Front Fog Lamps Malfunction 2. Front Fog Lamp Switch Malfunction

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

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

Conditions for Setting the DTC

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

Actions Taken When the DTC Sets

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

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

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

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

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Relay Replacement (Attached to Wire Harness)»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-repair-instructions) or «Relay Replacement (Within an Electrical Center)»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-repair-instructions)
  2. «Front Fog Lamp Replacement (Tahoe, Avalanche)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) or «Front Fog Lamp Replacement (Yukon)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) or «Front Fog Lamp Replacement (PLATINUM)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system)
  3. «Control Module References»(/cadillac/escalade/gmt900-2006-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM replacement, setup, and programming
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Rear Fog Lamp Relay ControlB2540 02B2540 05B2540 05
Rear Fog Lamp Switch SignalB3588 02
Rear Fog Lamp Control11
Headlamp Switch Ground1
Rear Fog Lamp Ground1
1. Rear Fog Lamps Malfunction

When the rear fog lamp switch is placed in the ON position, ground is applied to the auxiliary body control module (XBCM) through the rear fog lamp switch circuit. The XBCM then applies voltage to the rear fog lamp control circuit to the rear fog lamp.

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

B2540 02

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

B2540 05

The BCM detects a short to voltage or an open/high resistance in the rear fog lamp switch signal circuit.

The rear fog lamps 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 ignition cycles have occurred.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition OFF, disconnect the harness connector at the headlamp switch.
  2. Verify that a test lamp illuminates between B+ and the ground circuit terminal 8. If the test lamp does not illuminate, test the ground circuit for an open/high resistance.
  3. Ignition ON, verify the scan tool Rear Fog Lamp Switch parameter is INACTIVE. If not the specified value, test the signal circuit terminal 6 for a short to ground. If the circuit tests normal, replace the XBCM.
  4. Install a 3 A fused jumper wire between the signal circuit terminal 6 and ground. Verify the scan tool Rear Fog Lamp Switch parameter is ACTIVE. If not the specified value, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the XBCM.
  5. If all circuits test normal, test or replace the headlamp switch.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Rear Fog Lamp Bulb Replacement (Cadillac Export)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system)
  2. «Headlamp Switch Replacement (Cadillac)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) or «Headlamp Switch Replacement (Except Cadillac)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system)
  3. «Control Module References»(/cadillac/escalade/gmt900-2006-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for XBCM replacement, setup, and programming
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
VEH BCK/UP Fuse B+11
Backup Lamps Relay ControlB2545 0011
Backup Lamps Control111
Backup Lamp - Left Ground1
Backup Lamp - Right Ground1
Backup Lamp Relay Ground1
1. Backup Lamps Malfunction

When the transmission is placed in the REVERSE position, the transmission control module (TCM) sends a serial data message to the body control module (BCM). The message indicates that the gear selector is in the REVERSE position. The BCM applies voltage to the backup lamp relay control circuit energizing the backup lamp relay coil. With the relay coil energized, the switch contacts close allowing battery voltage to flow through the VEH BCK/UP fuse to the left and right backup lamps. The BCM also supplies voltage the to inside rearview mirror via the backup lamp relay control circuit for automatic day/night operation. Once the driver moves the gear selector out of the REVERSE position, a serial data message is sent by the TCM requesting the BCM to remove voltage from the backup lamp control circuit.

Battery voltage must be between 9-16 V.

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

The backup lamps will not operate.

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

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition OFF, disconnect the harness connector at the inside rearview mirror.
  2. Connect a test lamp between the control circuit terminal 9 and ground.
  3. Ignition ON, command the Backup Lamps ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states. If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the BCM. If the test lamp is always OFF, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM.
  4. Ignition OFF, connect the harness connector at the inside rearview mirror. Disconnect the X5 harness connector at the underhood fuse block.
  5. Connect a test lamp between the control circuit terminal H8 and ground.
  6. Ignition ON, command the Backup Lamps ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states. If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the BCM. If the test lamp is always OFF, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM.
  7. If all circuits test normal, replace the underhood fuse block.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Underhood Electrical Center or Junction Block Replacement»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-repair-instructions)
  2. «Control Module References»(/cadillac/escalade/gmt900-2006-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM, inside rearview mirror, and rearview camera module replacement, setup, and programming
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Left Courtesy Lamp Control CircuitB2555 021B2555 01
Right Courtesy Lamp Control CircuitB2555 021B2555 01
Courtesy Lamp Ground1
1. Courtesy Lamps Inoperative

When the body control module (BCM) signals for courtesy lamp operation, a message is sent over the serial data circuit to the driver door and passenger door switches. The driver door switch and passenger door switch the applies battery voltage to the left and right courtesy lamp control circuits illuminating the door courtesy lamps. The driver door and passenger door switches also provide ground to the lamps.

  1. Battery voltage must be between 9-16 V.
  2. A message is sent from the BCM over the serial data circuit to the driver door and passenger door switches to active the door courtesy lamps.

B2555 01

The driver or passenger door switch detects a short to voltage in the courtesy lamp control circuit.

B2555 02

The driver or passenger door switch detects a short to ground in the courtesy lamp control circuit.

  1. The condition responsible for setting the DTC no longer exists.
  2. A scan tool CLEAR DTCs command is issued for that switch module.
  3. A history DTC will clear once 100 consecutive malfunction-free ignition cycles have occurred.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

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

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

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Dome Lamp Replacement»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system)
  2. «Control Module References»(/cadillac/escalade/gmt900-2006-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for driver or passenger door switch replacement, setup, and programming
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Headlamp LO/HID Relay B+11
High Beam Relay B+22
Headlamp Flash to Pass Signal444
Headlamp Dimmer Switch Signal444
Headlamp Low Beam Control111
Headlamp Low Beam Relay Control11B2575 00
Headlamp Switch Off ControlB257A 0033
Headlamp Switch On ControlB257A 0033
Headlamp High Beam Control222
Headlamp High Beam Relay Control22B2580 00
Park Lamp Switch On ControlB257A 00B257A 003
Headlamp Switch Ground2
Turn Signal/Multifunction Switch Malfunction4
1. Headlamp Malfunction - Low Beam 2. Headlamp Malfunction - High Beam 3. Headlamp Switch Malfunction 4. Turn Signal/Multifunction Switch Malfunction

When the Headlamp and Panel Dimmer Switch is placed in the headlamp ON position, ground is applied to the body control module (BCM) through the headlamp low beam signal circuit. The BCM then applies ground to the HDLP LO/HID Relay control circuit which energizes the low beam relay. With the low beam relay energized, the switch contacts close allowing B+ to flow through the LOW HDLP fuses to the low beam headlamps.

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

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

The low beam headlamps will not operate.

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

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition OFF, disconnect the low beam headlamp relay.
  2. Ignition ON, verify that a test lamp does not illuminate between the control circuit terminal 87 and ground. If the test lamp illuminates, test the control circuit for a short to voltage.
  3. Verify that a test lamp illuminates between the B+ circuit terminal 85 and ground. If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance. If the circuit tests normal and the B+ circuit fuse is open, test the control circuit terminal 87 for a short to ground. If the circuit tests normal, test or replace the low beam headlamp relay.
  4. Verify that a test lamp illuminates between the B+ circuit terminal 30 and ground. If the test lamp does not illuminate, test the B+ circuit for an open/high resistance.
  5. Disconnect the harness connector at the appropriate head lamp.
  6. Test for less than 5 ohms between the head lamp ground circuit terminal listed below and ground: With X88 - Terminal A With Z88 - Terminal B If greater than the specified range, test the ground circuit for an open/high resistance.
  7. Connect the harness connector at the headlamp.
  8. Connect a 20 A fused jumper wire between the B+ circuit terminal 30 and the control circuit terminal 87. Verify the headlamp is activated. If the headlamp does not activate and the circuit fuse is good, test the control circuit for an open/high resistance. If the circuit tests normal, test or replace the headlamp. If the headlamp does not activate and the circuit fuse is open, test the control circuit for a short to ground. If the circuit tests normal, test or replace the headlamp.
  9. Connect a test lamp between the B+ circuit terminal 85 and the control circuit terminal 86.
  10. Command the Low Beams ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states. If the test lamp is always ON, test the control circuit for a short to ground. If the circuit tests normal, replace the BCM. If the test lamp is always OFF, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the BCM.
  11. If all circuits test normal, test or replace the low beam headlamp relay.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Relay Replacement (Attached to Wire Harness)»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-repair-instructions) or «Relay Replacement (Within an Electrical Center)»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-repair-instructions)
  2. «Headlamp Replacement (Cadillac Escalade)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) or «Headlamp Replacement (GMC Yukon Two-mode Hybrid)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) or «Headlamp Replacement (Yukon)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) or «Headlamp Replacement (Chevrolet Tahoe Two-mode Hybrid)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) or «Headlamp Replacement (Tahoe, Avalanche)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) or «Headlamp Replacement (Escalade PLATINUM)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) or «Headlamp Replacement (Non HID)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system)
  3. «Control Module References»(/cadillac/escalade/gmt900-2006-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM replacement, setup, and programming
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Daytime Running Lamp Relay B+11
Headlamp LO/HID Relay B+11
High Beam Relay B+11
Ambient Light Sensor Signal CircuitB2645 03B2645 07B2645 07
Headlamp Flash to Pass Signal444
Headlamp Dimmer Switch Signal444
Daytime Running Lamp Relay Control33B2600 00
Headlamp Low Beam Control111
Headlamp Low Beam Relay Control11B2575 00
Headlamp Switch Off ControlB257A 0022
Headlamp Switch On ControlB257A 0011
Headlamp High Beam Control111
Headlamp High Beam Relay Control11B2580 00
Park Lamp Switch On ControlB257A 00B257A 002
Ambient Light Sensor Ground CircuitB2645 07
Headlamp Switch Ground2
Turn Signal/Multifunction Switch Malfunction4
1. Headlamp Malfunction 2. Headlamp Switch Malfunction 3. Daytime Running Lamps Malfunction 4. Turn Signal/Multifunction Switch Malfunction

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

Battery voltage must be between 9-16 V

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

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

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition OFF, disconnect the X2 harness connector at the BCM.
  2. Connect a test lamp between B+ and the signal circuit terminal 17.
  3. Turn the headlamp switch between the AUTO and AUTO disable positions. The test lamp should turn ON and OFF as the switch is cycled. If the test lamp is always OFF, test the signal circuit for a short to voltage or an open/high resistance. If the circuit test normal, replace the headlamp and panel dimmer switch. If the test lamp is always ON, test the signal circuit for a short to ground. If the circuit test normal, replace the headlamp and panel dimmer switch.
  4. Connect a test lamp between B+ and the signal circuit terminal 3.
  5. Turn the headlamp switch to the ON and OFF positions. The test lamp should turn ON and OFF as the switch is cycled. If the test lamp is always OFF, test the signal circuit for a short to voltage or an open/high resistance. If the circuit test normal, replace the headlamp and panel dimmer switch. If the test lamp is always ON, test the signal circuit for a short to ground. If the circuit test normal, replace the headlamp and panel dimmer switch.
  6. If all circuits test normal, replace the BCM.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Headlamp Switch Replacement (Cadillac)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) or «Headlamp Switch Replacement (Except Cadillac)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system)
  2. «Control Module References»(/cadillac/escalade/gmt900-2006-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM replacement, setup, and programming
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Headlamp LO/HID Relay B+11
High Beam Relay B+22
Headlamp Flash to Pass Signal444
Headlamp Dimmer Switch Signal444
Headlamp Low Beam Control111
Headlamp Low Beam Relay Control11B2575 00
Headlamp Switch Off ControlB257A 0033
Headlamp Switch On ControlB257A 0033
Headlamp High Beam Control222
Headlamp High Beam Relay Control22B2580 00
Park Lamp Switch On ControlB257A 00B257A 003
Headlamp Switch Ground2
Turn Signal/Multifunction Switch Malfunction4
1. Headlamp Malfunction - Low Beam 2. Headlamp Malfunction - High Beam 3. Headlamp Switch Malfunction 4. Turn Signal/Multifunction Switch Malfunction

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

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

The BCM detects a short to voltage in the headlamp HIGH BEAM relay control circuit.

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

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

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition OFF, disconnect the X4 harness connector at the underhood fuse block.
  2. Connect a test lamp between the control circuit terminal C3 and B+.
  3. Command the High Beams ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states. If the test lamp is always ON, test the control circuit for a short to ground. If the circuit tests normal, replace the BCM. If the test lamp is always OFF, test the control circuit for a short to voltage or open/high resistance. If the circuit tests normal, replace the BCM.
  4. If all circuits test normal, test or replace the underhood fuse block.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Underhood Electrical Center or Junction Block Replacement»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-repair-instructions)
  2. «Control Module References»(/cadillac/escalade/gmt900-2006-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM replacement, setup, and programming
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Park Lamp Relay B+11
Park Lamp Switch Signal222
Park Lamp Relay Control11B2585 00
Park Lamp Control111
Headlamp and Panel Dimmer Switch Ground1
1. Park Lamp Malfunction 2. Park Lamp Switch Malfunction

Voltage is applied at all times to the park lamp relay from battery voltage. When the headlamp switch is placed in the PARK position and the body control module (BCM) commands the park lamps ON, the BCM then applies a ground to the park lamp relay control circuit. This engages the relay and applies voltage through the park lamp fuses and to all the park, license, and tail lamps.

  1. The Ignition is ON.
  2. The park lamps must be commanded ON by the BCM.

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

All park, license, and tail lamps are inoperative.

  1. The conditions for setting the DTC are no longer present.
  2. A history DTC clears after 100 malfunction-free ignition cycles.
  3. The BCM receives the clear code command from the scan tool.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

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

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Relay Replacement (Attached to Wire Harness)»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-repair-instructions) or «Relay Replacement (Within an Electrical Center)»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-repair-instructions)
  2. «Headlamp Replacement (Cadillac Escalade)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) or «Headlamp Replacement (GMC Yukon Two-mode Hybrid)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) or «Headlamp Replacement (Yukon)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) or «Headlamp Replacement (Chevrolet Tahoe Two-mode Hybrid)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) or «Headlamp Replacement (Tahoe, Avalanche)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) or «Headlamp Replacement (Escalade PLATINUM)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) or «Headlamp Replacement (Non HID)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system)
  3. «Repeater Lamp Replacement (Escalade)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system)
  4. «Front Side Marker Lamp Replacement (Yukon)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) or «Front Side Marker Lamp Replacement (Tahoe, Avalanche)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system)
  5. «Parking and Turn Signal Lamp Replacement (Tahoe, Avalanche)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) or «Parking and Turn Signal Lamp Replacement (Yukon)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system)
  6. «Tail Lamp Replacement (Avalanche)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) or «Tail Lamp Replacement (GMC Yukon Two-Mode Hybrid)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) or «Tail Lamp Replacement (Chevrolet Tahoe Two-Mode Hybrid)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system__tail-lamp-replacement-chevrolet-tahoe-two-mode) or «Tail Lamp Replacement (Cadillac)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system__tail-lamp-replacement-cadillac) or «Tail Lamp Replacement (Tahoe, Yukon)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system)
  7. «Control Module References»(/cadillac/escalade/gmt900-2006-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM replacement, setup, and programming
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Daytime Running Lamp Relay B+11
Headlamp LO/HID Relay B+11
High Beam Relay B+11
Ambient Light Sensor Signal CircuitB2645 03B2645 07B2645 07
Headlamp Flash to Pass Signal444
Headlamp Dimmer Switch Signal444
Daytime Running Lamp Relay Control33B2600 00
Headlamp Low Beam Control111
Headlamp Low Beam Relay Control11B2575 00
Headlamp Switch Off ControlB257A 0022
Headlamp Switch On ControlB257A 0011
Headlamp High Beam Control111
Headlamp High Beam Relay Control11B2580 00
Park Lamp Switch On ControlB257A 00B257A 002
Ambient Light Sensor Ground CircuitB2645 07
Headlamp Switch Ground2
Turn Signal/Multifunction Switch Malfunction4
1. Headlamp Malfunction 2. Headlamp Switch Malfunction 3. Daytime Running Lamps Malfunction 4. Turn Signal/Multifunction Switch Malfunction

The ambient light sensor is used to monitor outside lighting conditions. The ambient light sensor provides a voltage signal that will vary between 0.2 and 4.9 V depending on outside lighting conditions. The body control module (BCM) provides a 5 V reference signal to the ambient light sensor. The body control module (BCM) monitors the ambient light sensor signal circuit to determine if outside lighting conditions are correct for either daytime running lights (DRL) or automatic lamp control (ALC) when the headlamp switch is in the AUTO position. In daylight conditions, the BCM will command the DRLs ON by applying ground to the DRL relay via the DRL relay control circuit. When the BCM applies ground to the DRL relay control circuit, the DRL relay coil energizes causing the relay switch contacts to close. With the DRL relay energized, voltage is applied through the relay switch contacts, the DRL Resistor, and the DRL fuse to the left and right low beam headlamp fuses illuminating the low beam headlamps. Any function or condition that turns the headlamps ON will cancel DRL operation. Any function or condition that turns on the headlamps will cancel DRL operation.

  1. Battery voltage must be between 9-16 V.
  2. Headlamp switch in AUTO position.

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

The BCM will disable the DRL relay control circuit.

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

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

WARNINGThe high intensity discharge system produces high voltage and current. To reduce the risk of severe shocks and burns: Never open the high intensity discharge system ballast or the arc tube assembly starter. Never probe between the high intensity discharge system ballast output connector and the arc tube assembly.
  1. Ignition OFF, disconnect the X4 harness connector at the fuse block - underhood.
  2. Connect a test lamp between the control circuit terminal H4 and B+.
  3. Command the DRLs ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states. If the test lamp is always ON, test the control circuit for a short to ground. If the circuit tests normal, replace the BCM. If the test lamp is always OFF, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the BCM.
  4. Ignition OFF, connect the X4 harness connector at the fuse block - underhood. Disconnect the harness connector at the daytime running lamp.
  5. Test for less than 5 ohms between the daytime running lamp ground circuit terminal listed below and ground: With X88 - Terminal C With Z75 and Z88 - Terminal B If greater than the specified range, test the ground circuit for an open/high resistance.
  6. Connect a test lamp between control circuit terminal A and ground
  7. Command the DRLs ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states. If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the fuse block - underhood. If the test lamp is always OFF and the circuit fuse is good, test the control circuit for an open/high resistance. If the circuit tests normal, test or replace the fuse block - underhood. If the test lamp is always OFF and the circuit fuse is open, test the control circuit for a short to ground. If the circuit tests normal, test or replace the daytime running lamp.
  8. If all circuits test normal, test or replace the daytime running lamp.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Headlamp Replacement (Cadillac Escalade)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) or «Headlamp Replacement (GMC Yukon Two-mode Hybrid)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) or «Headlamp Replacement (Yukon)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) or «Headlamp Replacement (Chevrolet Tahoe Two-mode Hybrid)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) or «Headlamp Replacement (Tahoe, Avalanche)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) or «Headlamp Replacement (Escalade PLATINUM)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) or «Headlamp Replacement (Non HID)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system)
  2. «Underhood Electrical Center or Junction Block Replacement»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-repair-instructions)
  3. «Control Module References»(/cadillac/escalade/gmt900-2006-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM replacement, setup, and programming
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Headlamp LO/HID Relay B+11
Daytime Running Lamp Resistor Control22B2600 00
Headlamp Low Beam Control111
1. Headlamp Malfunction 2. Daytime Running Lamps Malfunction

The ambient light sensor is used to monitor outside lighting conditions. The ambient light sensor provides a voltage signal that will vary between 0.2 and 4.9 V depending on outside lighting conditions. The body control module (BCM) provides a 5 V reference signal to the ambient light sensor. The body control module (BCM) monitors the ambient light sensor signal circuit to determine if outside lighting conditions are correct for either daytime running lights (DRL) or automatic lamp control (ALC) when the headlamp switch is in the AUTO position. In daylight conditions, the BCM will command the DRLs ON by applying ground to the DRL resistor via the DRL resistor control circuit. When the BCM applies ground to the DRL resistor control circuit, the DRL signal circuits to the right and left headlamp assemblies are pulled low. The DRL signal circuits are direct inputs to the right and left headlamp control modules. When the DRL signal circuits are provided with ground, the right and left headlamp control modules respond by turning OFF the low beam headlamps and activating the DRLs. Any function or condition that turns the headlamps ON will cancel DRL operation.

  1. Battery voltage must be between 9-16 V.
  2. Headlamp switch in AUTO position.

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

  1. The Service Headlamp Assembly indicator is commanded ON.
  2. The BCM will disable the DRL resistor control circuit.
  1. The condition responsible for setting the DTC no longer exists.
  2. A history DTC will clear once 100 consecutive malfunction-free ignition cycles have occurred.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition OFF, disconnect the harness connector at the DRL resistor.
  2. Connect a test lamp between the control circuit terminal C and B+.
  3. Command the DRL ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states. If the test lamp is always ON, test the control circuit for a short to ground. If the circuit tests normal, replace the BCM. If the test lamp is always OFF, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the BCM.
  4. Ignition OFF, connect the harness connector at the DRL resistor.
  5. Disconnect the harness connector at the inoperative headlamp assembly.
  6. Connect a test lamp between the signal circuit terminal D and B+.
  7. Command the DRL ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states. If the test lamp is always ON, test the signal circuit for a short to ground. If the circuit tests normal, replace the DRL resistor. If the test lamp is always OFF, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the DRL resistor.
  8. Connect a test lamp between the signal circuit terminal B and B+.
  9. Command the DRL ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states. If the test lamp is always ON, test the signal circuit for a short to ground. If the circuit tests normal, replace the DRL resistor. If the test lamp is always OFF, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the DRL resistor.
  10. If all circuits test normal, replace the appropriate headlamp.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Headlamp Replacement (Cadillac Escalade)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) or «Headlamp Replacement (GMC Yukon Two-mode Hybrid)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) or «Headlamp Replacement (Yukon)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) or «Headlamp Replacement (Chevrolet Tahoe Two-mode Hybrid)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) or «Headlamp Replacement (Tahoe, Avalanche)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) or «Headlamp Replacement (Escalade PLATINUM)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) or «Headlamp Replacement (Non HID)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system)
  2. «Underhood Electrical Center or Junction Block Replacement»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-repair-instructions)
  3. «Control Module References»(/cadillac/escalade/gmt900-2006-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM replacement, setup, and programming
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
I/P Dimming Voltage ReferenceB1395 03, B3600 03B1395 03, B2652 00, B3600 03B1395 07
Courtesy Lamp Voltage ReferenceB2615 00, B2615 02B2615 00, B2615 04B2615 00, B2615 01
LED Dimming Voltage ReferenceB2610 00B2610 00B2610 00
LED Indicator Dimming Volage ReferenceB2625 00B2625 00B2625 00
Dome Lamp Switch Signal222
Left Front Door Open Switch Signal333
Left Rear Door Open Switch Signal444
Right Front Door Open Switch Signal333
Right Rear Door Open Switch Signal444
Stop Lamp Switch SignalB1395 03, B3600 03
Dome/Reading Lamp ControlB2615 00B2615 00
Dome/Reading Lamp Supply Voltage11
Exterior Lamps Illumination Supply Voltage555
Inadvertent Power Control555
I/P Lamps Dimming ControlB2652 00B2652 00B2652 00
Dome/Reading Lamp Low Control - Driver Door1
Dome/Reading Lamp Low Control - Passenger Door1
Exterior Lamps Low Reference5
I/P Dimmer Switch Ground2
LH Vanity Mirror Courtesy Lamp Ground1
Overhead Console Courtesy Lamp Ground1
Rear Dome Lamp Ground1
RH Vanity Mirror Courtesy Lamp Ground1
1. Courtesy Lamps Malfunction 2. Dome Lamp Switch Malfunction 3. Door Open Switch Malfunction - Front 4. Door Open Switch Malfunction - Rear 5. Exterior Lamps Malfunction

When the instrument panel lamps dimmer switch is activated, a variable voltage signal is applied through the LED dimmer switch signal circuit to the body control module (BCM). The BCM then applies a message on the low speed serial data communication circuit to the door switches to illuminate the switch backlighting. The BCM, driver door switch, and passenger door switch then applies a variable voltage signal through the LED dimming supply circuit to the components on that circuit.

  1. Battery Voltage be between 9-16 V.
  2. The ignition is ON.

The BCM, driver door switch, and passenger door switch detect a short to voltage, short to ground, or an open on the LED dimming supply circuit.

The BCM, driver door switch, and passenger door switch will cease attempts to dim or illuminate the LED lamps.

  1. The conditions for setting the DTC are no longer present.
  2. A history DTC clears after 100 malfunction-free ignition cycles.
  3. The BCM receives the clear code command from the scan tool.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

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

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

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. Refer to the appropriate replacement procedure for the component causing the condition.
  2. «Control Module References»(/cadillac/escalade/gmt900-2006-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM replacement, setup, and programming
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
I/P Dimming Voltage ReferenceB1395 03, B3600 03B1395 03, B2652 00, B3600 03B1395 07
Courtesy Lamp Voltage ReferenceB2615 00, B2615 02B2615 00, B2615 04B2615 00, B2615 01
LED Dimming Voltage ReferenceB2610 00, B2610 02B2610 00, B2610 04B2610 00, B2610 01
LED Indicator Dimming Volage ReferenceB2625 00B2625 00B2625 00
Dome Lamp Switch Signal222
Left Front Door Open Switch Signal333
Left Rear Door Open Switch Signal444
Right Front Door Open Switch Signal333
Right Rear Door Open Switch Signal444
Stop Lamp Switch SignalB1395 03, B3600 03
Dome/Reading Lamp ControlB2615 00B2615 00
Dome/Reading Lamp Supply Voltage11
Exterior Lamps Illumination Supply Voltage555
Inadvertent Power Control555
I/P Lamps Dimming ControlB2652 00B2652 00B2652 00
Dome/Reading Lamp Low Control - Driver Door1
Dome/Reading Lamp Low Control - Passenger Door1
Exterior Lamps Low Reference5
I/P Dimmer Switch Ground2
LH Vanity Mirror Courtesy Lamp Ground1
Overhead Console Courtesy Lamp Ground1
Rear Dome Lamp Ground1
RH Vanity Mirror Courtesy Lamp Ground1
1. Courtesy Lamps Malfunction 2. Dome Lamp Switch Malfunction 3. Door Open Switch Malfunction - Front 4. Door Open Switch Malfunction - Rear 5. Exterior Lamps Malfunction

Voltage for the courtesy lamps is supplied from body control module (BCM), driver door switch, and passenger door switch. When a door is opened, a signal is applied to the door module. The door module then applies a message on the low speed serial data communication circuit to the BCM to activate the courtesy lamps. The BCM then applies voltage to the courtesy lamps voltage supply circuit and the components on that circuit.

  1. Battery Voltage must be between 9-16 V.
  2. The ignition is ON.
  3. The BCM, driver door switch, and passenger door switch attempt to illuminate the courtesy lamps.

The BCM, driver door switch, or passenger door switch detect a short to ground, short to voltage, or open on the courtesy lamp voltage supply circuit.

The BCM, driver door switch, and passenger door switch cease attempts to illuminate the courtesy lamps.

  1. The conditions for setting the DTC are no longer present.
  2. A history DTC clears after 100 malfunction-free ignition cycles.
  3. The BCM receives the clear code command from the scan tool.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

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

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

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. Refer to the appropriate replacement procedure for the component causing the condition.
  2. «Control Module References»(/cadillac/escalade/gmt900-2006-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM replacement, setup, and programming
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
I/P Dimming Voltage ReferenceB1395 03, B3600 03B1395 03, B2652 00, B3600 03B1395 07
Courtesy Lamp Voltage ReferenceB2615 00, B2615 02B2615 00, B2615 04B2615 00, B2615 01
LED Dimming Voltage ReferenceB2610 00, B2610 02B2610 00, B2610 04B2610 00, B2610 01
LED Indicator Dimming Volage ReferenceB2625 00B2625 00B2625 00
Dome Lamp Switch Signal222
Left Front Door Open Switch Signal333
Left Rear Door Open Switch Signal444
Right Front Door Open Switch Signal333
Right Rear Door Open Switch Signal444
Stop Lamp Switch SignalB1395 03, B3600 03
Dome/Reading Lamp ControlB2615 00B2615 00
Dome/Reading Lamp Supply Voltage11
Exterior Lamps Illumination Supply Voltage555
Inadvertent Power Control555
I/P Lamps Dimming ControlB2652 00B2652 00B2652 00
Dome/Reading Lamp Low Control - Driver Door1
Dome/Reading Lamp Low Control - Passenger Door1
Exterior Lamps Low Reference5
I/P Dimmer Switch Ground2
LH Vanity Mirror Courtesy Lamp Ground1
Overhead Console Courtesy Lamp Ground1
Rear Dome Lamp Ground1
RH Vanity Mirror Courtesy Lamp Ground1
1. Courtesy Lamps Malfunction 2. Dome Lamp Switch Malfunction 3. Door Open Switch Malfunction - Front 4. Door Open Switch Malfunction - Rear 5. Exterior Lamps Malfunction

When the interior lamps dimming switch is activated, a variable voltage signal is applied through the instrument panel lamps dimmer switch signal circuit to the body control module (BCM). The BCM then applies a variable voltage signal through the LED indicator dimming supply circuit to the components on the circuit.

The ignition is ON.

The BCM receives a ground signal on the LED indicator dimming supply circuit.

The BCM cease attempt to dim or illuminate the LED indicator lamps.

  1. The conditions for setting the DTC are no longer present.
  2. A history DTC clears after 100 malfunction-free ignition cycles.
  3. The BCM receives the clear code command from the scan tool.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

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

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

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. Refer to the appropriate replacement procedure for the component causing the condition.
  2. «Control Module References»(/cadillac/escalade/gmt900-2006-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM replacement, setup, and programming
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Headlamp LO/HID Relay B+11
High Beam Relay B+22
Headlamp Flash to Pass Signal444
Headlamp Dimmer Switch Signal444
Headlamp Low Beam Control111
Headlamp Low Beam Relay Control11B2575 00
Headlamp Switch Off ControlB257A 0033
Headlamp Switch On ControlB257A 0033
Ambient Light Sensor SignalB2645 03B2645 07B2645 07
Headlamp High Beam Control222
Headlamp High Beam Relay Control22B2580 00
Park Lamp Switch On ControlB257A 00B257A 003
Headlamp Switch Ground2
Turn Signal/Multifunction Switch Malfunction4
Headlamp Malfunction - Low Beam Headlamp Malfunction - High Beam Headlamp Switch Malfunction Turn Signal/Multifunction Switch Malfunction

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

Battery voltage must be between 9-16 V.

B2645 03

The BCM detects voltage is below 0.196 volt in the ambient light sensor signal circuit.

B2645 07

The BCM detects voltage is above 4.9 volts in the ambient light sensor signal circuit or if the ambient light sensor ground circuit is open.

The automatic lamp control will default to ON.

  1. The condition responsible for setting the DTC no longer exists.
  2. You issue a scan tool CLEAR DTCs command.
  3. A history DTC will clear once 100 consecutive malfunction-free ignition cycles have occurred.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition OFF, disconnect the harness connector at the ambient light sensor.
  2. Test for less than 5.0 ohms between the ground circuit listed below and ground. Ambient Light Sensor terminal C - CJ2 Ambient Light Sensor terminal B - w/o CJ2 If greater than the specified range, test the ground circuit for an open/high resistance.
  3. Ignition ON, verify the scan tool Ambient Light Sensor parameter is greater than 4.5 V. If less than the specified range, test the signal circuit for a short to ground. If the circuit tests normal, replace the BCM.
  4. Install a 3 A fused jumper wire between the signal circuit terminal listed below and the low reference circuit terminal listed below. Verify the scan tool Ambient Light Sensor parameter is less than 1.0 V. Ambient Light Sensor terminals A to B - w/o CJ2 Ambient Light Sensor terminals D to C - CJ2 If greater than the specified range, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the BCM.
  5. If all circuits test normal, test or replace the ambient light sensor.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Ambient Light Sensor Replacement»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system)
  2. «Control Module References»(/cadillac/escalade/gmt900-2006-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM replacement, setup, and programming
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
I/P Dimming Voltage ReferenceB1395 03, B3600 03B1395 03, B2652 00, B3600 03B1395 07
Courtesy Lamp Voltage ReferenceB2615 00, B2615 02B2615 00, B2615 04B2615 00, B2615 01
LED Dimming Voltage ReferenceB2610 00, B2610 02B2610 00, B2610 04B2610 00, B2610 01
LED Indicator Dimming Volage ReferenceB2625 00B2625 00B2625 00
Dome Lamp Switch Signal222
Left Front Door Open Switch Signal333
Left Rear Door Open Switch Signal444
Right Front Door Open Switch Signal333
Right Rear Door Open Switch Signal444
Stop Lamp Switch SignalB1395 03, B3600 03
Dome/Reading Lamp ControlB2615 00B2615 00
Dome/Reading Lamp Supply Voltage11
Exterior Lamps Illumination Supply Voltage555
Inadvertent Power Control555
I/P Lamps Dimming ControlB2652 00B2652 00B2652 00
Dome/Reading Lamp Low Control - Driver Door1
Dome/Reading Lamp Low Control - Passenger Door1
Exterior Lamps Low Reference5
I/P Dimmer Switch Ground2
LH Vanity Mirror Courtesy Lamp Ground1
Overhead Console Courtesy Lamp Ground1
Rear Dome Lamp Ground1
RH Vanity Mirror Courtesy Lamp Ground1
1. Courtesy Lamps Malfunction 2. Dome Lamp Switch Malfunction 3. Door Open Switch Malfunction - Front 4. Door Open Switch Malfunction - Rear 5. Exterior Lamps Malfunction

The body control module (BCM) applies a 12 V reference voltage through the headlamp and panel dimmer switch 12 V reference circuit to the headlamp and panel dimmer switch. When the dimming switch is placed in the desired position, the dimmed voltage setting is applied from the headlamp and panel dimmer switch through the instrument panel (I/P) lamp dimming switch signal circuit to the BCM. The BCM then applies the dimmed voltage to the I/P lamp dimming control circuit and the components on the circuit.

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

The BCM receives an open, voltage, or ground signal on the I/P lamp dimming control circuit.

The I/P lamps are not illuminated.

  1. The conditions for setting the DTC are no longer present.
  2. A history DTC clears after 100 malfunction-free ignition cycles.
  3. The BCM receives the clear code command from the scan tool.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

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

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. Refer to the appropriate replacement procedure for the component causing the condition.
  2. «Control Module References»(/cadillac/escalade/gmt900-2006-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM replacement, setup, and programming
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Stop Lamp Relay Switch B+11
Stop Lamp Switch B+ Voltage ReferenceB1395 03, B3600 0311
Stop Lamp Switch Signal111
Stop Lamp Relay ControlB3445 0011
Tail/Stop Lamp Control - Left111
Tail/Stop Lamp Control - Right111
Center High Mounted Stop Lamp (CHMSL) Ground2
Tail/Stop Lamp Ground - Left1
Tail/Stop Lamp Ground - Right1
Stop Lamp Relay Ground1
1. Stop Lamps Malfunction 2. Center High Mounted Stop Lamp (CHMSL) Malfunction

The stop lamp switch is used to sense the action of the driver application of the brake pedal. The body control module (BCM) provides a low reference signal and a B+ reference voltage to the stop lamp switch. When the stop lamp switch contacts close indicating the brakes have been applied, the BCM will apply battery voltage to stop lamp relay control circuit and the center high mounted stop lamp (CHMSL). When the stop lamp relay receives battery voltage from the BCM, the relay coil is energized and the stop lamp relay switch contacts close applying battery voltage to the STOP LAMPS fuse to illuminate the left and right stop lamps.

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

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

The BCM will not illuminate the CHMSL.

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

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

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

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Tail Lamp Bulb Replacement (Yukon)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) or «Tail Lamp Bulb Replacement (Cadillac)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system__tail-lamp-bulb-replacement-cadillac) or «Tail Lamp Bulb Replacement (Tahoe, Avalanche)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) or «Tail Lamp Bulb Replacement (Tahoe)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) or «Tail Lamp Bulb Replacement (Yukon Two-mode Hybrid)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system)
  2. «High Mount Stop Lamp Replacement (Yukon Two-mode Hybrid)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) or «High Mount Stop Lamp Replacement (Yukon)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) or «High Mount Stop Lamp Replacement (Avalanche)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) or «High Mount Stop Lamp Replacement (Escalade)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system)
  3. «Control Module References»(/cadillac/escalade/gmt900-2006-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM replacement, setup, and programming
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Rear Fog Lamp Relay ControlB2540 02B2540 05B2540 05
Rear Fog Lamp Switch SignalB3588 02
Rear Fog Lamp Control11
Headlamp Switch Ground1
Rear Fog Lamp Ground1
1. Rear Fog Lamps Malfunction

The auxiliary body control module (XBCM) receives a momentary ground signal from the rear fog lamp switch when the switch is activated. The rear fog lamps will remain illuminated until the switch is activated again or when the ignition key is cycled.

System voltage to the XBCM must be 9-16 V.

The rear fog lamp switch signal circuit is active for longer than 10 minutes.

The rear fog lamps will be disabled.

  1. The DTC will be current for as long as the fault is present.
  2. When the fault is no longer present, the DTC will be a history status code.
  3. A history DTC will clear after 50 ignition cycles or with a scan tool using the clear DTCs function.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

System Verification

Ignition ON, observe the scan tool Rear Fog Lamp Switch parameter while turning the rear fog lamp switch ON and OFF. The parameter should change between Active and Inactive.

  1. Ignition OFF, disconnect the harness connector at the headlamp and panel dimmer switch.
  2. Ignition OFF, verify a test lamp illuminates between B+ and the ground circuit terminal 8. If the test lamp does not illuminate, test the ground circuit for an open/high resistance.
  3. Verify the scan tool Rear Fog Lamp Switch parameter displays Inactive. If not the specified value, test the signal circuit terminal 6 for a short to ground. If the circuit tests normal, replace the XBCM.
  4. Install a 3 A fused jumper wire between the signal circuit terminal 6 and the ground circuit terminal 8. Verify the scan tool Rear Fog Lamp Switch parameter is Active. If not the specified value, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the XBCM.
  5. If all circuits test normal, replace the headlamp and panel dimmer switch.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Headlamp Switch Replacement (Cadillac)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) or «Headlamp Switch Replacement (Except Cadillac)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system)
  2. «Control Module References»(/cadillac/escalade/gmt900-2006-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for XBCM replacement, setup, and programming
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
I/P Dimming Voltage ReferenceB1395 03, B3600 03B1395 03, B2652 00, B3600 03B1395 07
Courtesy Lamp Voltage ReferenceB2615 00, B2615 02B2615 00, B2615 04B2615 00, B2615 01
LED Dimming Voltage ReferenceB2610 00, B2610 02B2610 00, B2610 04B2610 00, B2610 01
LED Indicator Dimming Volage ReferenceB2625 00B2625 00B2625 00
Dome Lamp Switch Signal222
Left Front Door Open Switch Signal333
Left Rear Door Open Switch Signal444
Right Front Door Open Switch Signal333
Right Rear Door Open Switch Signal444
Stop Lamp Switch SignalB1395 03, B3600 03
Dome/Reading Lamp ControlB2615 00B2615 00
Dome/Reading Lamp Supply Voltage11
Exterior Lamps Illumination Supply Voltage555
Inadvertent Power Control555
I/P Lamps Dimming ControlB2652 00B2652 00B2652 00
Dome/Reading Lamp Low Control - Driver Door1
Dome/Reading Lamp Low Control - Passenger Door1
Exterior Lamps Low Reference5
I/P Dimmer Switch Ground2
LH Vanity Mirror Courtesy Lamp Ground1
Overhead Console Courtesy Lamp Ground1
Rear Dome Lamp Ground1
RH Vanity Mirror Courtesy Lamp Ground1
1. Courtesy Lamps Malfunction 2. Dome Lamp Switch Malfunction 3. Door Open Switch Malfunction - Front 4. Door Open Switch Malfunction - Rear 5. Exterior Lamps Malfunction

Voltage for the interior backlighting components is supplied from the body control module (BCM). The BCM applies a voltage reference through the 12 V reference circuit to the headlamp and panel dimmer switch. When the dimming switch is placed in the desired position, the dimmed voltage setting is applied from the headlamp and panel dimmer switch through the instrument panel (I/P) lamp dimmer switch signal circuit to the BCM. The BCM then applies the dimmed voltage to the lamp supply voltage circuits and they are dimmed to the correct level.

The ignition is ON.

B3600 03

The BCM detects a voltage that is lower than 0.10 V on the I/P lamp dimmer switch signal circuit.

B3600 07

The BCM detects a voltage that is higher than 4.97 V on the I/P lamp dimmer switch signal circuit.

The I/P lamps are not illuminated.

The BCM clears this code from current when the fault is removed from the system.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

Ignition ON, headlamp switch to HEAD, vary the interior lamp dimming switch from dim to full bright. The I/P lamps should dim and then become full bright.

  1. Ignition OFF, disconnect the harness connector at the headlamp and panel dimmer switch.
  2. Ignition OFF, verify that a test lamp illuminates between the ground circuit terminal 8 and B+. If the test lamp does not illuminate, test the ground circuit for an open/high resistance.
  3. Ignition ON, verify the scan tool Dimming Control Signal parameter is less than 0.1 V. If greater than the specified range, test the signal circuit terminal 13 for a short to voltage. If the circuit tests normal, replace the BCM.
  4. Ignition ON, test for 12 V between the I/P dimming voltage reference circuit terminal 15 and ground. If less than the specified value, test the voltage reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM.
  5. Install a 3 A fused jumper wire between the signal circuit terminal 13 and the voltage reference circuit terminal 15. Verify the scan tool BCM Dimming Control Signal parameter is greater than 2.6 V. If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM.
  6. If all circuits test normal, test or replace the headlamp switch.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Headlamp Switch Replacement (Cadillac)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) or «Headlamp Switch Replacement (Except Cadillac)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system)
  2. «Control Module References»(/cadillac/escalade/gmt900-2006-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM replacement, setup, and programming
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
MISC IGN Fuse B+ Supply11
Stop Lamp Switch 12 V ReferenceB3445 003
STOP LAMPS Fuse B+ Supply11
Left Outage Detection Signal111
Left Outage Detection Signal - European444
Right Outage Detection Signal111
Right Outage Detection Signal - European444
Stop Lamp Switch Signal33
Stop Lamp Switch Control111
Center High Mounted Stop Lamp (CHMSL) ControlB3884 0022
Left Lower Tail/Stop and Turn Signal Lamp Control111
Left Upper Tail/Stop and Turn Lamp Control111
Left Tail Lamp Control Circuit Board Control111
Left Tail Lamp Control Circuit Board Control - European444
Right Lower Tail/Stop and Turn Signal Lamp Control111
Right Upper Tail/Stop and Turn Signal Lamp Control111
Right Tail Lamp Control Circuit Board Control111
Right Tail Lamp Control Circuit Board Control - European444
Center High Mounted Stop Lamp (CHMSL) Ground2
Left Upper Tail/Stop and Turn Signal Lamp Ground1
Left Tail Lamp Control Circuit Board Ground1
Left Lower Tail/Stop and Turn Signal Lamp Ground1
Left Tail/Stop Lamp Ground1
Left Tail Lamp Circuit Board Ground - European4
Right Lower Tail/Stop and Turn Signal Lamp Ground1
Right Lower Tail/Stop and Turn Signal Lamp Ground1
Right Tail Lamp Control Circuit Board Ground1
Right Tail/Stop Lamp Ground1
Right Tail Lamp Circuit Board - European4
1. Stop Lamps Malfunction - North American 2. Center High Mounted Stop Lamp (CHMSL) Malfunction 3. Stop Lamp Switch Malfunction 4. Stop Lamps Malfunction - European

North American or European

The stop lamp switch is used to sense the action of the driver application of the brake pedal. The body control module (BCM) provides a low reference signal and a B+ reference voltage to the stop lamp switch. When the stop lamp switch contacts close indicating the brakes have been applied, the BCM will apply battery voltage to stop lamp relay control circuit and the center high mounted stop lamp (CHMSL). When the stop lamp relay receives battery voltage from the BCM, the relay coil is energized and the stop lamp relay switch contacts close applying battery voltage to the STOP LAMPS fuse to illuminate the left and right stop lamps.

  1. The ignition is ON.
  2. The stop lamps must be commanded ON.

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

The CHMSL will not illuminate.

  1. The conditions for setting the DTC are no longer present.
  2. A history DTC clears after 100 malfunction-free ignition cycles.
  3. The BCM receives the clear code command from the scan tool.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

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

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «High Mount Stop Lamp Replacement (Yukon Two-mode Hybrid)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) or «High Mount Stop Lamp Replacement (Yukon)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) or «High Mount Stop Lamp Replacement (Avalanche)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) or «High Mount Stop Lamp Replacement (Escalade)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system)
  2. «Control Module References»(/cadillac/escalade/gmt900-2006-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM replacement, setup, and programming
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Rear Fog Lamp Switch Signal CircuitB3891 02B3891 05B3891 05
Rear Fog Lamp Ground CircuitB3891 05
Rear Fog Lamp Switch Signal Circuit12
Rear Fog Lamp Switch Ground Circuit2
1. Fog Lamp Always On - Rear 2. Fog Lamp Inoperative - Rear

When the rear fog lamp switch is placed in the ON position, ground is applied to the auxiliary body control module (XBCM) through the rear fog lamp switch circuit. The XBCM then applies voltage on the trailer fog lamp circuit to the trailer rear fog lamp.

The ignition is ON. Park lamps must be ON and the rear fog lamps must be commanded ON.

The body control module (BCM) detects an open, short to ground, or short to voltage on the trailer rear fog lamp circuit while trying to apply a voltage to the circuit.

The trailer rear fog lamps do not illuminate.

  1. The conditions for setting the DTC are no longer present.
  2. A history DTC clears after 100 malfunction-free ignition cycles.
  3. The BCM receives the clear code command from the scan tool.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Inspect the trailer rear fog lamp bulb for an open or shorted filament. If the bulb is inoperable, replace the bulb.
  2. Park lamp switch OFF, clear the DTC, test the trailer rear fog lamp circuit for a short to voltage, short to ground, an open, or high resistance. If all circuits/connections test normal, replace the XBCM.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for XBCM replacement, setup, and programming

  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

Battery voltage must be between 9-16 V.

In the event that DTC C0277, C0297, or C0890 sets as current in the body control module (BCM) is an indication of a possible internal BCM malfunction or programming error. There are no external circuits available to diagnose on this vehicle with respect to these DTCs.

When DTC C0277 is set as current, the vehicle may not start.

  1. For DTC C0277 the ignition must be cycled before the code can be cleared.
  2. A history DTC will clear once 50 malfunction-free ignition cycles have occurred.
  3. A DTC will not clear the current status until the next ignition cycle.

Diagnostic Aids

These DTCs may set as current after the replacement of an electronic brake control module (EBCM) or engine control module (ECM). If a control module has been replaced, ensure that the programming procedure and all recalibration procedures have been completed successfully before addressing these DTCs.

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition ON, verify that the DTC is set as current and that no other vehicle system DTCs exists. If other vehicle system DTCs exists, address these DTCs before proceeding with this diagnostic test.
  2. Cycle the ignition OFF then ON, clear the DTC with a scan tool and verify that the DTC does not reset as current. If the DTC resets as current, replace the BCM.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for BCM replacement, setup, and programming

Symptoms - Lighting

  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) , before using the Symptom Tables in order to verify that all of the following are true: There are no DTCs set. The control modules can communicate via the serial data link.
  2. Review the system operation in order to familiarize yourself with the system functions. Refer to the following: «Exterior Lighting Systems Description and Operation»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) «Interior Lighting Systems Description and Operation»(/cadillac/escalade/gmt900-2006-2014/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/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__checking-aftermarket-accessories) .
  2. Inspect the easily accessible or visible system components for obvious damage or conditions which could cause the symptom.

Intermittent

Faulty electrical connections or wiring may be the cause of intermittent conditions. 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/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system)
  2. «Courtesy Lamps Malfunction»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system)
  3. «Daytime Running Lamps Malfunction (With Z88, Z75, and Z88)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) or «Daytime Running Lamps Malfunction (With T4Q)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system)
  4. «Door Sill Illumination Malfunction»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system)
  5. «Front Fog Lamps Malfunction»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system)
  6. «Rear Fog Lamps Malfunction»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system)
  7. «Hazard Lamps Malfunction»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system)
  8. «Headlamps Malfunction (With X88, Z75, and Z88)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) or «Headlamps Malfunction (With T4Q)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system)
  9. «High Intensity Discharge Lamp Malfunction»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system)
  10. «Interior Backlighting Malfunction»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system)
  11. «Park, License, and/or Tail Lamps Malfunction (With X88, Z75, and Z88)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) or «Park, License, and/or Tail Lamps Malfunction (Front LED Park/Marker Lamps with T4Q)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system)
  12. «Stop Lamps Malfunction»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system)
  13. «Turn Signal Lamps and/or Indicators Malfunction»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system)
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
VEH BCK/UP Fuse B+B2545 00B2545 00
Backup Lamps ControlB2545 0011
Backup Lamp - Left Ground1
Backup Lamp - Right Ground1
Backup Lamp Relay Ground1
1. Backup Lamps Malfunction

When the transmission is placed in the REVERSE position, the transmission control module (TCM) sends a serial data message to the body control module (BCM). The message indicates that the gear selector is in the REVERSE position. The BCM applies voltage to the backup lamp relay control circuit energizing the backup lamp relay coil. With the relay coil energized, the switch contacts close allowing battery voltage to flow through the VEH BCK/UP fuse to the left and right backup lamps. The BCM also supplies voltage the to inside rearview mirror via the backup lamp relay control circuit for automatic day/night operation. Once the driver moves the gear selector out of the REVERSE position, a serial data message is sent by the TCM requesting the BCM to remove voltage from the backup lamp control circuit.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

Command the Backup Lamps ON and OFF with a scan tool. The backup lamps should turn ON and OFF when commanded.

  1. Ignition OFF, disconnect the harness connector at the inside rearview mirror.
  2. Connect a test lamp between the control circuit terminal 9 and ground.
  3. Ignition ON, command the Backup Lamps ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states. If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the BCM. If the test lamp is always OFF, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM.
  4. Connect the harness connector at the inside rearview mirror.
  5. Ignition OFF, disconnect the harness connector X5 at the BCM.
  6. Connect a test lamp between the control circuit terminal 7 and ground.
  7. Ignition ON, command the Backup Lamps ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states. If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the BCM. If the test lamp is always OFF, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM.
  8. Ignition OFF, disconnect the harness connector at the inoperative backup lamp.
  9. Ignition OFF, exterior lamps OFF, test for less than 5.0 ohms between the ground circuit terminal listed below and ground: With HP2 - Terminal B With X88 - Terminal A With Z75 - E52 - Terminal GRD With Z88 - Terminal 1 If greater than the specified range, test the ground circuit for an open/high resistance.
  10. Connect a test lamp between the control circuit terminal listed below and ground: With HP2 - Terminal B With X88 - Terminal A With Z75 - E52 - Terminal GRD With Z88 - Terminal 1
  11. Ignition ON, command the Backup Lamps ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states. If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the BCM. If the test lamp is always OFF, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM.
  12. If all circuits test normal, test or replace the inoperative backup lamp.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Tail Lamp Bulb Replacement (Yukon)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) or «Tail Lamp Bulb Replacement (Cadillac)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system__tail-lamp-bulb-replacement-cadillac) or «Tail Lamp Bulb Replacement (Tahoe, Avalanche)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) or «Tail Lamp Bulb Replacement (Tahoe)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) or «Tail Lamp Bulb Replacement (Yukon Two-mode Hybrid)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system)
  2. «Tail Lamp Replacement (Avalanche)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) or «Tail Lamp Replacement (GMC Yukon Two-Mode Hybrid)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) or «Tail Lamp Replacement (Chevrolet Tahoe Two-Mode Hybrid)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system__tail-lamp-replacement-chevrolet-tahoe-two-mode) or «Tail Lamp Replacement (Cadillac)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system__tail-lamp-replacement-cadillac) or «Tail Lamp Replacement (Tahoe, Yukon)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system)
  3. «Control Module References»(/cadillac/escalade/gmt900-2006-2014/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/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
I/P Dimming Voltage ReferenceB1395 03B1395 03B1395 07
Courtesy Lamp Voltage ReferenceB2615 00, B2615 02B2615 00, B2615 04B2615 00, B2615 01
LED Indicator Dimming Volage ReferenceB2625 00B2625 00B2625 00
Dome/Reading Lamp ControlB2615 00B2615 00
Dome/Reading Lamp Supply Voltage11
Dome Lamp Switch Signal222
Exterior Lamps Illumination Supply Voltage555
Inadvertent Power Control555
I/P Lamps Dimming ControlB2652 00B2652 00B2652 00
Left Front Door Open Switch Signal333
Left Rear Door Open Switch Signal444
Right Front Door Open Switch Signal333
Right Rear Door Open Switch Signal444
Dome/Reading Lamp Low Control - Driver Door1
Dome/Reading Lamp Low Control - Passenger Door1
Exterior Lamps Low Reference5
I/P Dimmer Switch Ground2
LH Vanity Mirror Courtesy Lamp Ground1
Overhead Console Courtesy Lamp Ground1
Rear Dome Lamp Ground1
RH Vanity Mirror Courtesy Lamp Ground1
1. Courtesy Lamps Malfunction 2. Dome Lamp Switch Malfunction 3. Door Open Switch Malfunction - Front 4. Door Open Switch Malfunction - Rear 5. Exterior Lamps Malfunction

Voltage for the courtesy lamps is supplied from body control module (BCM), driver door switch, and passenger door switch. When a door is opened, a signal is applied to the door module. The door module then applies a message on the low speed GMLAN serial data communication circuit to the BCM to activate the courtesy lamps. The BCM then applies voltage to the courtesy lamps voltage supply circuit and the components on that circuit.

Schematic Reference

  1. «Interior Lights Schematics»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system)
  2. «Interior Lights Dimming Schematics»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system)

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition ON, observe the scan tool Door Ajar Sw. parameter while opening and closing each vehicle door. The parameter should change between Door Ajar and Door Closed. If the parameter does not change between the selected states, refer to «Door Ajar Indicator Malfunction»(/cadillac/escalade/gmt900-2006-2014/remont/door-locks-anti-theft-systems/#door-lock-system-door-handles) .
  2. Observe the scan tool Rear Closure Ajar Sw. parameter while opening and closing the trunk. The parameter should change between Active and Inactive. If the parameter does not change between the selected states, refer to «Liftgate Ajar Indicator Malfunction (RPO TB7)»(/cadillac/escalade/gmt900-2006-2014/remont/door-locks-anti-theft-systems/#door-lock-system-door-handles) or «Liftgate/Liftgate Window Ajar Indicator Malfunction (Manual Liftgate)»(/cadillac/escalade/gmt900-2006-2014/remont/door-locks-anti-theft-systems/#door-lock-system-door-handles) or «Liftgate/Liftgate Window Ajar Indicator Malfunction (Power Liftgate)»(/cadillac/escalade/gmt900-2006-2014/remont/door-locks-anti-theft-systems/#door-lock-system-door-handles)
  3. Command the Courtesy Lamps ON and OFF with a scan tool. The courtesy lamps should turn ON and OFF when changing between the commanded states. If the courtesy lamps do not turn ON and OFF when commanded, refer to «Circuit/System Testing»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) .
  4. All doors closed, observe the scan tool Ctsy. Lamp Actv. Reason parameter while turning the dome lamp switch ON and OFF. The reading should change between Off and Manual. If the Ctsy. Lamp Actv. Reason parameter does not change between Off and Manual, refer to Dome/Interior Lamp Switch Malfunction in «Circuit/System Testing»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) .
  5. All doors closed, observe the scan tool Ctsy. Lamp Actv. Reason parameter while turning the interior lamp defeat switch ON and OFF. The reading should change between Off and Manual Defeat. If the Ctsy. Lamp Actv. Reason parameter does not change between Off and Manual, refer to Dome/Interior Lamp Switch Malfunction in «Circuit/System Testing»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) .
  6. Turn the individual reading lamps ON and OFF with their respective switches. The reading lamps should turn ON and OFF when changing between the selected states. If any reading lamp does not turn ON and OFF when selected, refer to Reading Lamps Malfunction in «Circuit/System Testing»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) .
  7. Turn the left and right vanity mirror lamps ON and OFF with their respective switches. The vanity mirror lamps should turn ON and OFF when changing between the selected states. If any reading lamp does not turn ON and OFF when selected, refer to Vanity Mirror Lighting Malfunction in «Circuit/System Testing»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) .
  8. Command the Courtesy Lamp ON and OFF with a scan tool. Verify the exterior illumination lamps turn ON and OFF. If the exterior illumination lamps do not change between ON and OFF, refer to Outside Rearview Mirror Illumination Malfunction in «Circuit/System Testing»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) .

Courtesy Lamp Malfunction

  1. Ignition OFF, disconnect the harness connector at the appropriate lamp.
  2. Test for less than 5.0 ohms between the ground circuit terminal B and ground. If greater than the specified range, test the ground circuit for an open/high resistance.
  3. Connect a test lamp between the control circuit terminal listed below and the ground. Courtesy/Reading Lamp terminal A Dome/Reading Lamp terminal C Door Courtesy Lamp terminal A Sunshade Lamps terminal A Dome Lamp terminal A Cargo Lamp terminal A
  4. Ignition ON, command the Courtesy Lamps output control ON and OFF with the scan tool. The test lamp should turn ON and OFF. If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the BCM. If the test lamp is always OFF, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM.
  5. If all circuits test normal, test or replace the courtesy lamp.

Dome/Interior Lamp Switch Malfunction

  1. Ignition OFF, disconnect the harness connector at the headlamp and panel dimmer switch.
  2. Test for less than 5.0 ohms between the ground circuit terminal 8 and ground. If greater than the specified range, test the ground circuit for an open/high resistance.
  3. Ignition ON, verify the scan tool Ctsy. Lamp Actv. Reason parameter is Off. If the parameter is Manual or Manual Defeat, test the appropriate signal circuit terminal for a short to ground. If the circuit tests normal, replace the BCM. Manual terminal 12 Manual Defeat terminal 9
  4. Install a 3 A fused jumper wire between the signal circuit terminal 12 and the ground circuit terminal 8. Verify the scan tool Ctsy. Lamp Actv. Reason parameter is Manual. If not the specified value, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the BCM.
  5. Install a 3 A fused jumper wire between the signal circuit terminal 9 and the ground circuit terminal 8. Verify the scan tool Ctsy. Lamp Actv. Reason parameter is Manual Defeat. If not the specified value, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the BCM.
  6. If all circuits test normal, test or replace the headlamp and panel dimmer switch.

Reading Lamps Malfunction

  1. Ignition OFF, disconnect the X3 harness connector at the BCM.
  2. Verify a test lamp illuminates between the IS LPS fuse B+ circuit terminal 2 and ground. If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.
  3. Reconnect the X3 harness connector at the BCM.
  4. Disconnect the harness connector at the inoperative courtesy/reading lamp assembly.
  5. Scan tool OFF, doors CLOSED, interior lamps OFF, test for less than 5.0 ohms between the ground circuit terminal B and ground.
  6. Verify a test lamp illuminates between the control circuit terminal listed below and ground: Courtesy/Reading Lamp terminal C Dome/Reading Lamp terminal A If the test lamp does not illuminate, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM.
  7. Remove the IS LPS fuse and verify the test lamp turns OFF. If the test lamp remains illuminated, test the control circuit for a short to voltage. If the circuit tests normal, replace the BCM.
  8. If all circuits test normal, replace the courtesy lamp assembly.

Vanity Mirror Lighting Malfunction

  1. Ignition OFF, disconnect the harness connector at the appropriate vanity mirror lamp.
  2. Test for less than 5.0 ohms between the ground circuit terminal B and ground. If greater than the specified range, test the ground circuit for an open/high resistance.
  3. Ignition ON, verify that a test lamp illuminates between the control circuit terminal A and ground. If the test lamp does not illuminate, test the inadvertent power supply circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM.
  4. Connect the harness connector at the vanity mirror lamp.
  5. Remove the IS LPS fuse and verify the test lamp turns OFF. If the test lamp remains illuminated, test the control circuit for a short to voltage. If the circuit tests normal, replace the BCM.
  6. If all circuits test normal, replace the vanity mirror.

Outside Rearview Mirror Illumination Malfunction

  1. Disconnect the harness connector at the appropriate exterior illumination lamp.
  2. Ignition ON, verify that a test lamp illuminates between the exterior illumination lamp supply circuit terminal and ground. If the test lamp does not illuminate, test the exterior illumination lamp supply circuit for a short to ground or an open/high resistance.
  3. Connect a test lamp between the low side control circuit terminal and the exterior illumination lamp supply circuit terminal.
  4. Command the Courtesy Lamp ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states. If the test lamp is always ON, test the control circuit for a short to ground. If the circuit tests normal, replace the inoperative door switch. If the test lamp is always OFF, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the inoperative door switch.
  5. If all circuits test normal, test or replace the appropriate lamp.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Dome Lamp Replacement»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system)
  2. «Door Courtesy Lamp and Reflector Replacement»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system)
  3. «Door Lock and Side Window Switch Replacement - Driver Side»(/cadillac/escalade/gmt900-2006-2014/remont/door-locks-anti-theft-systems/#door-lock-system-door-handles)
  4. «Front Side Door Lock Replacement»(/cadillac/escalade/gmt900-2006-2014/remont/door-locks-anti-theft-systems/#door-lock-system-door-handles)
  5. «Rear Side Door Lock Replacement»(/cadillac/escalade/gmt900-2006-2014/remont/door-locks-anti-theft-systems/#door-lock-system-door-handles)
  6. «Headlamp Switch Replacement (Cadillac)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) or «Headlamp Switch Replacement (Except Cadillac)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system)
  7. «Control Module References»(/cadillac/escalade/gmt900-2006-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM, driver door switch, or passenger door switch replacement, setup, and programming
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Daytime Running Lamp Relay B+11
Headlamp LO/HID Relay B+11
High Beam Relay B+11
Ambient Light Sensor Signal CircuitB2645 03B2645 07B2645 07
Headlamp Flash to Pass Signal444
Headlamp Dimmer Switch Signal444
Daytime Running Lamp Relay Control33B2600 00
Headlamp Low Beam Control111
Headlamp Low Beam Relay Control11B2575 00
Headlamp Switch Off ControlB257A 0022
Headlamp Switch On ControlB257A 0011
Headlamp High Beam Control111
Headlamp High Beam Relay Control11B2580 00
Park Lamp Switch On ControlB257A 00B257A 002
Ambient Light Sensor Ground CircuitB2645 07
Headlamp Switch Ground2
Turn Signal/Multifunction Switch Malfunction4
1. Headlamp Malfunction 2. Headlamp Switch Malfunction 3. Daytime Running Lamps Malfunction 4. Turn Signal/Multifunction Switch Malfunction

Daytime Running Lamps without HID

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

Daytime Running Lamps with HID

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

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

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition ON, Headlamps OFF, command the Low Beams ON and OFF with a scan tool. The low beam headlamps should turn ON and OFF when changing between the commanded states. If the low beam headlamps do not change between the commanded states, refer to «Headlamps Malfunction (With X88, Z75, and Z88)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) or «Headlamps Malfunction (With T4Q)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) .
  2. Headlamps OFF, command the DRL ON and OFF with a scan tool. The daytime running lights should turn ON and OFF when changing between the commanded states. If the daytime running lights do not change between the commanded states, refer to Daytime Running Lamp Malfunction in «Circuit/System Testing»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) .
  3. Observe the scan tool Ambient Light Status parameter while supplying sufficient light to simulate daylight conditions to the ambient light sensor. After 30 seconds, the parameter should be Day. If not the specified value, refer to Ambient Light Sensor Malfunction in «Circuit/System Testing»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) .

Daytime Running Lamp Malfunction - with Z75/X88

  1. Ignition OFF, disconnect the harness connector X4 at the underhood fuse block.
  2. Connect a test lamp between the daytime running lamps relay control circuit terminal H4 and B+.
  3. Ignition ON, command the DRL ON and OFF with a scan tool. The test lamp should turn ON and OFF between the commanded states. If the test lamp is always ON, test the control circuit for a short to ground. If the circuit tests normal, replace the BCM. If the test lamp is always OFF, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the BCM.
  4. Ignition OFF, reconnect the harness connector X4 at the underhood fuse block.
  5. Disconnect the harness connector at the appropriate daytime running lamp.
  6. Test for less then 5 ohms between the ground circuit listed below and ground. Terminal B (Z75) Terminal C (X88) If less than the specified range, test the ground circuit for an open/high resistance.
  7. Ignition OFF, connect a test lamp between the control circuit terminal A and ground.
  8. Ignition ON, command the DRL ON and OFF with a scan tool. The test lamp should turn ON and OFF. If the test lamp is always ON, test the control circuit for a short to voltage. If the control circuit tests normal, replace the underhood fuse block. If the test lamp is always OFF, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, and the DRL fuse is not open, replace the underhood fuse block.
  9. If all circuits test normal, replace the daytime running lamp.

Daytime Running Lamp Malfunction - with Z88

  1. Ignition OFF, disconnect the harness connector X4 at the underhood fuse block.
  2. Connect a test lamp between the daytime running lamps relay control circuit terminal H4 and B+.
  3. Ignition ON, command the DRL ON and OFF with a scan tool. The test lamp should turn ON and OFF between the commanded states. If the test lamp is always ON, test the control circuit for a short to ground. If the circuit tests normal, replace the BCM. If the test lamp is always OFF, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the BCM.
  4. Ignition OFF, reconnect the harness connector X4 at the underhood fuse block.
  5. Disconnect the harness connector at the appropriate headlamp.
  6. Test for less then 5 ohms between the ground circuit terminal B and ground. If more than the specified range, test the ground circuit for an open/high resistance.
  7. Ignition OFF, connect a test lamp between the control circuit terminal A and ground.
  8. Ignition ON, command the DRL ON and OFF with a scan tool. The test lamp should turn ON and OFF. If the test lamp is always ON, test the control circuit for a short to voltage. If the control circuit tests normal, replace the underhood fuse block. If the test lamp is always OFF, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, and the DRL fuses are not open, replace the underhood fuse block.
  9. If all circuits test normal, replace the headlamp.

Ambient Light Sensor Malfunction

  1. Ignition OFF, disconnect the harness connector at the ambient light sensor.
  2. Ignition OFF, test for less than 5 ohms between the ground circuit terminal listed below and ground. Terminal C (with CJ2) Terminal B (without CJ2) If greater than the specific range, test the ground circuit for an open/high resistance.
  3. Ignition ON, verify the scan tool Ambient Light Sensor parameter is greater than 4.65 V. If less than the specified range, test the signal circuit terminal for a short to ground. If the circuit tests normal, replace the BCM.
  4. Install a 3 A fused jumper wire between the signal circuit terminal listed below and the ground circuit terminal. Verify the scan tool Ambient Light Sensor parameter is less than 0.196 V. Terminal D (with CJ2) Terminal A (without CJ2) If greater than the specified range, test the signal circuit for a short to voltage an open/high resistance. If the circuit tests normal, replace the BCM.
  5. If all circuits test normal, replace the ambient light sensor.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Headlamp Replacement (Cadillac Escalade)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) or «Headlamp Replacement (GMC Yukon Two-mode Hybrid)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) or «Headlamp Replacement (Yukon)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) or «Headlamp Replacement (Chevrolet Tahoe Two-mode Hybrid)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) or «Headlamp Replacement (Tahoe, Avalanche)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) or «Headlamp Replacement (Escalade PLATINUM)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) or «Headlamp Replacement (Non HID)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system)
  2. «Headlamp Bulb Replacement (Cadillac)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) or «Headlamp Bulb Replacement (Tahoe, Avalanche)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) or «Headlamp Bulb Replacement (Yukon)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system)
  3. «Ambient Light Sensor Replacement»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system)
  4. «Daytime Running Lamp Bulb Replacement (GMC)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) or «Daytime Running Lamp Bulb Replacement (Cadillac)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system)
  5. «Underhood Electrical Center or Junction Block Replacement»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-repair-instructions)
  6. «Control Module References»(/cadillac/escalade/gmt900-2006-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM or headlamp control module replacement, setup, and programming
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Daytime Running Lamp Relay B+11
Headlamp LO/HID Relay B+11
High Beam Relay B+11
Ambient Light Sensor Signal CircuitB2645 03B2645 07B2645 07
Headlamp Flash to Pass Signal444
Headlamp Dimmer Switch Signal444
Daytime Running Lamp Relay Control33B2600 00
Headlamp Low Beam Control111
Headlamp Low Beam Relay Control11B2575 00
Headlamp Switch Off ControlB257A 0022
Headlamp Switch On ControlB257A 0011
Headlamp High Beam Control111
Headlamp High Beam Relay Control11B2580 00
Park Lamp Switch On ControlB257A 00B257A 002
Ambient Light Sensor Ground CircuitB2645 07
Headlamp Switch Ground2
Turn Signal/Multifunction Switch Malfunction4
1. Headlamp Malfunction 2. Headlamp Switch Malfunction 3. Daytime Running Lamps Malfunction 4. Turn Signal/Multifunction Switch 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 V reference signal to the ambient light sensor. The body control module (BCM) monitors the ambient light sensor signal circuit to determine if outside lighting conditions are correct for either daytime running lights (DRL) or automatic lamp control (ALC) when the headlamp switch is in the AUTO position. In daylight conditions, the BCM will command the DRLs ON by applying ground to the DRL resistor via the DRL resistor control circuit. When the BCM applies ground to the DRL resistor control circuit, the DRL signal circuits to the right and left headlamp assemblies are pulled low. The DRL signal circuits are direct inputs to the right and left headlamp control modules. When the DRL signal circuits are provided with ground, the right and left headlamp control modules respond by turning OFF the low beam headlamps and activating the DRLs. Any function or condition that turns the headlamps ON will cancel DRL operation.

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

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition ON, Headlamps OFF, command the Low Beams ON and OFF with a scan tool. The low beam headlamps should turn ON and OFF when changing between the commanded states. If the low beam headlamps do not change between the commanded states, refer to «Headlamps Malfunction (With X88, Z75, and Z88)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) or «Headlamps Malfunction (With T4Q)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) .
  2. Headlamps OFF, command the DRL ON and OFF with a scan tool. The daytime running lights should turn ON and OFF when changing between the commanded states. If the daytime running lights do not change between the commanded states, refer to Daytime Running Lamp Malfunction in «Circuit/System Testing»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) .
  3. Observe the scan tool Ambient Light Status parameter while supplying sufficient light to simulate daylight conditions to the ambient light sensor. After 30 seconds, the parameter should be Day. If not the specified value, refer to Ambient Light Sensor Malfunction in «Circuit/System Testing»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) .

Daytime Running Lamp Malfunction

  1. Ignition OFF, disconnect the harness connector at the DRL resistor.
  2. Connect a test lamp between the control circuit terminal C and B+.
  3. Command the DRL ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states. If the test lamp is always ON, test the control circuit for a short to ground. If the circuit tests normal, replace the BCM. If the test lamp is always OFF, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the BCM.
  4. Ignition OFF, connect the harness connector at the DRL resistor.
  5. Disconnect the harness connector at the appropriate headlamp assembly.
  6. Connect a test lamp between the signal circuit terminal D and B+.
  7. Command the DRL ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states. If the test lamp is always ON, test the signal circuit for a short to ground. If the circuit tests normal, replace the DRL resistor. If the test lamp is always OFF, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the DRL resistor.
  8. Connect a test lamp between the signal circuit terminal B and B+.
  9. Command the DRL ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states. If the test lamp is always ON, test the signal circuit for a short to ground. If the circuit tests normal, replace the DRL resistor. If the test lamp is always OFF, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the DRL resistor.
  10. If all circuits test normal, replace the headlamp assembly.

Ambient Light Sensor Malfunction

  1. Ignition OFF, disconnect the harness connector at the ambient light sensor.
  2. Ignition OFF, test for less than 5 ohms between the ground circuit terminal listed below and ground. Terminal C (with CJ2) Terminal B (without CJ2) If greater than the specific range, test the ground circuit for an open/high resistance.
  3. Ignition ON, verify the scan tool Ambient Light Sensor parameter is greater than 4.65 V. If less than the specified range, test the signal circuit terminal for a short to ground. If the circuit tests normal, replace the BCM.
  4. Install a 3 A fused jumper wire between the signal circuit terminal listed below and the ground circuit terminal. Verify the scan tool Ambient Light Sensor parameter is less than 0.196 V. Terminal D (with CJ2) Terminal A (without CJ2) If greater than the specified range, test the signal circuit for a short to voltage an open/high resistance. If the circuit tests normal, replace the BCM.
  5. If all circuits test normal, replace the ambient light sensor.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Ambient Light Sensor Replacement»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system)
  2. «Headlamp Replacement (Cadillac Escalade)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) or «Headlamp Replacement (GMC Yukon Two-mode Hybrid)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) or «Headlamp Replacement (Yukon)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) or «Headlamp Replacement (Chevrolet Tahoe Two-mode Hybrid)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) or «Headlamp Replacement (Tahoe, Avalanche)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) or «Headlamp Replacement (Escalade PLATINUM)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) or «Headlamp Replacement (Non HID)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system)
  3. «Headlamp Control Module Replacement (Escalade PLATINUM)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system)
  4. «Control Module References»(/cadillac/escalade/gmt900-2006-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM or headlamp control module replacement, setup, and programming
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
ControlB2615 00B2615 001
Ground2
1. Door Sill Illumination Always On 2. Door Sill Illumination Inoperative

When the BCM receives a signal to command the courtesy lamps ON, it applies battery voltage through the dome/courtesy lamps control circuit to the courtesy lamps. The door sill illumination receives voltage through the courtesy lamps circuit. The door sill illumination harness connector includes a power inverter which converts the battery voltage to 150 V AC (550 Hz). This AC voltage is supplied to the door sill lamps and causes them to illuminate.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Observe the vehicle entry courtesy lamps while opening and closing the driver door. The entry courtesy lamps should turn ON the door is opened and OFF when the door is closed. If the entry courtesy lamps do not change between the selected states, refer to «Courtesy Lamps Malfunction»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) .
  2. Observe the door sill plate lamps while opening and closing the driver door. The door sill plate lamps should turn ON when the door is opened and turn OFF when the door is closed. If a single door sill plate lamp does not change between the selected states, replace the appropriate door sill plate lamp component. If all of the door sill plate lamps do not change between the selected states, refer to Circuit/System Testing in «Circuit/System Testing»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) .
WARNINGDC and AC high-voltage is present. To reduce the risk of severe shocks and burns, the high-voltage system should be disabled any time service work is being performed on or around the high-voltage system. When in doubt, always disable the high-voltage system. The 12-volt system will still be active after the high-voltage system has been disabled.
  1. Ignition OFF, verify door sill plate lamp ground circuit 1150 is securely connected to the driver side kick panel ground stud. If the door sill plate lamp ground circuit is not securely connected, repair the poor connection.
  2. Disconnect the X2 (blue) harness connector at the BCM.
  3. Using the appropriate test tool, connect a test lamp between the control circuit terminal 5 at the BCM and ground.
  4. Ignition ON, turn the door sill plate lamp ON and OFF by opening and closing the vehicle door. The test lamp should turn ON and OFF when changing between the selected states. If the test lamp is always ON or OFF, replace the BCM.
  5. If all circuits test normal, replace the door sill plate lamp kit.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for BCM replacement, setup, and programming

  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Front Fog Lamp Switch Signal222
Front Fog Lamp Relay Control11B2530 00
Front Fog Lamp Control111
Fog Lamp - LF Ground1
Fog Lamp - RF Ground1
Fog Lamp Switch Ground2
1. Front Fog Lamps Malfunction 2. Front Fog Lamp Switch Malfunction

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

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition ON, observe the scan tool Front Fog Lamp Switch parameter while activating the front fog lamp switch. The parameter should change between Active and Inactive. If the parameter does not change between the commanded states, refer to Front Fog Lamp Switch Malfunction in «Circuit/System Testing»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) .
  2. Turn the front fog lamps ON and OFF with the front fog lamps switch. The front fog lamps should turn ON and OFF as selected. If the front fog lamps do not change between the selected states, refer to Front Fog Lamps Malfunction in «Circuit/System Testing»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) .
  3. Command the Lamp Test ON and OFF with a scan tool. The front fog lamps indicator should turn ON and OFF when changing between the commanded states. If the front fog lamps indicator illuminates during the test, replace the BCM. If the front fog lamps indicator does not illuminate during the test or remains illuminated at all times, replace the instrument cluster.

Front Fog Lamp Switch Malfunction

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

Front Fog Lamps Malfunction

  1. Ignition OFF, disconnect the front fog lamp relay.
  2. Ignition ON, verify a test lamp does not illuminate between the control circuit terminal 87 and ground. If the test lamp illuminates, test the control circuit for a short to voltage.
  3. Verify a test lamp illuminates between the B+ circuit terminal 30 and ground. If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.
  4. Verify a test lamp illuminates between the B+ circuit terminal 85 and ground. If the test lamp does not illuminate, test the B+ circuit for an open/high resistance.
  5. Disconnect the harness connector at the appropriate front fog lamp.
  6. Ignition OFF, test for less than 5.0 ohms between the ground circuit terminal B and ground. If greater than the specified range, test the ground circuit for an open/high resistance.
  7. Connect the harness connector at the front fog lamp.
  8. Connect a 15 A fused jumper wire between the B+ circuit terminal 30 and the control circuit terminal 87. Verify the front fog lamps are activated. If the front fog lamps do not activate, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the front fog lamp.
  9. Connect a test lamp between the B+ circuit terminal 85 and the control circuit terminal 86.
  10. Ignition ON, command the Fog Lamps ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states. If the test lamp is always ON, test the control circuit for a short to ground. If the circuit tests normal, replace the BCM. If the test lamp is always OFF, test the control circuit for a short to voltage or open/high resistance. If the circuit tests normal, replace the BCM.
  11. If all circuits test normal, test or replace the front fog lamp relay.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Front Fog Lamp Bulb Replacement (Yukon)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) or «Front Fog Lamp Bulb Replacement (Tahoe)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) or «Front Fog Lamp Bulb Replacement (Escalade)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system)
  2. «Fog Lamp Switch Replacement»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system__fog-lamp-switch-replacement)
  3. «Headlamp Switch Replacement (Cadillac)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) or «Headlamp Switch Replacement (Except Cadillac)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system)
  4. «Relay Replacement (Attached to Wire Harness)»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-repair-instructions) or «Relay Replacement (Within an Electrical Center)»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-repair-instructions)
  5. «Control Module References»(/cadillac/escalade/gmt900-2006-2014/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/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Rear Fog Lamp Switch Signal11
Rear Fog Lamp ControlB2540 0212
Rear Fog Lamp Ground1
1. Rear fog lamp inoperative 2. Rear fog lamp always on

The auxiliary body control module (XBCM) controls and supplies battery positive voltage to both the rear fog lamp and trailer rear fog lamp circuits.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition ON, observe the scan tool Rear Fog Lamp Switch parameter while turning the rear fog lamp switch ON and OFF. The parameter should change between Active and Inactive. If the parameter does not change between the selected states, refer to Rear Fog Lamp Switch Malfunction in «Circuit/System Testing»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) .
  2. Turn the rear fog lamps ON and OFF with the front fog lamps switch. The rear fog lamps should turn ON and OFF as selected. If the rear fog lamps do not change between the selected states, refer to Rear Fog Lamps Malfunction in «Circuit/System Testing»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) .
  3. Command the Lamp Test ON and OFF with a scan tool. The rear fog lamps indicator should turn ON and OFF when changing between the commanded states. If the rear fog lamps indicator illuminates during the test, replace the BCM. If the rear fog lamps indicator does not illuminate during the test or remains illuminated at all times, replace the instrument cluster.

Rear Fog Lamp Switch Malfunction

  1. Ignition OFF, disconnect the harness connector at the headlamp and panel dimmer switch.
  2. Test for less than 1 ohms between the ground circuit terminal 8 and ground. If greater than the specified range, test the ground circuit for an open/high resistance.
  3. Ignition ON, verify the scan tool Rear Fog Lamp Switch parameter is Inactive. If not the specified value, test the signal circuit terminal 6 for a short to ground. If the circuit tests normal, replace the XBCM.
  4. Install a 3 A fused jumper wire between the signal circuit terminal 6 and the ground circuit terminal 8. Verify the scan tool Rear Fog Lamp Switch parameter is Active. If not the specified value, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the XBCM.
  5. If all circuits test normal, test or replace the headlamp and panel dimmer switch.

Rear Fog Lamps Malfunction

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

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Rear Fog Lamp Bulb Replacement (Cadillac Export)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system)
  2. «Headlamp Switch Replacement (Cadillac)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) or «Headlamp Switch Replacement (Except Cadillac)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system)
  3. «Rear Fog Lamp Replacement (Cadillac Export)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system)
  4. «Control Module References»(/cadillac/escalade/gmt900-2006-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for XBCM replacement, programming, and setup
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Hazard Switch Signal21
Hazard Switch Ground1
1. Hazard Flashers Inoperative 2. Hazard Flashers Always On

The hazard switch signal circuit is referenced from battery voltage by the BCM. When the hazard switch is activated, the signal circuit is grounded through the switch and the signal circuit voltage goes low. The BCM then sends an ON-OFF voltage signal through the fuses to the appropriate turn signal and side repeater (export only) lamps or to all of the turn signal fuses for hazard operation.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for Scan Tool Information

  1. Ignition ON, observe the scan tool Hazard Lamp Switch parameter while turning the hazard lamp switch ON and OFF. The reading should change between Active and Inactive. If the parameter does not change between the commanded states, refer to the Circuit/System Testing in «Circuit/System Testing»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) .
  2. Observe the right and left turn signal lamps while turning the hazard lamp switch ON and OFF. The right and left turn signal lamps should flash ON and OFF while the hazard lamp switch is ON and remain OFF when the hazard lamp switch is OFF. If the turn signal lamps do not cycle between the selected states, refer to «Turn Signal Lamps and/or Indicators Malfunction»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) .
  3. Command the Lamp Test ON and OFF with a scan tool. The left and right turn signal indicators should turn ON and OFF when changing between the commanded states. If the left and right turn signal indicators illuminate during the test, replace the BCM. If the left and right turn signal indicators do not illuminate during the test or remain illuminated at all times, replace the instrument cluster.
  1. Ignition OFF, disconnect the harness connector X1 at the turn signal/multifunction switch.
  2. Test for less than 1 ohms between the ground circuit terminal C and ground. If greater than the specified range, test the ground circuit for an open/high resistance.
  3. Ignition ON, verify the scan tool Hazard Lamp Switch parameter is Inactive. If not the specified value, test the signal circuit terminal G for a short to ground. If the circuit tests normal, replace the BCM.
  4. Install a 3 A fused jumper wire between the signal circuit terminal G and the ground circuit terminal C. Verify the scan tool Hazard Lamp Switch parameter is Active. If not the specified value, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the BCM.
  5. If all circuits test normal, test or replace the turn signal/multifunction switch

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Turn Signal Multifunction Switch Replacement»(/cadillac/escalade/gmt900-2006-2014/remont/steering-column-switches/#steering-wheel-steering-column)
  2. «Control Module References»(/cadillac/escalade/gmt900-2006-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM replacement, setup, and programming
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Relay Coil Control211
Headlamp Low Beam Control112
Low Beam Headlamp Ground1
1. Low Beam Headlamps Inoperative 2. Low Beam Headlamps Always ON

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

The following symptoms are noticeable signs of bulb failure

  1. Lights go out, caused when the ballast detects excessive, repetitive bulb re-strike.
  2. Color change-The lamp may change to a dim pink glow.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

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

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Relay Replacement (Attached to Wire Harness)»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-repair-instructions) or «Relay Replacement (Within an Electrical Center)»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-repair-instructions)
  2. «Headlamp Ballast Replacement»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system)
  3. «Headlamp Replacement (Cadillac Escalade)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) or «Headlamp Replacement (GMC Yukon Two-mode Hybrid)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) or «Headlamp Replacement (Yukon)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) or «Headlamp Replacement (Chevrolet Tahoe Two-mode Hybrid)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) or «Headlamp Replacement (Tahoe, Avalanche)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) or «Headlamp Replacement (Escalade PLATINUM)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) or «Headlamp Replacement (Non HID)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system)
  4. «Control Module References»(/cadillac/escalade/gmt900-2006-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM replacement, setup and programming
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Headlamp LO/HID Relay B+11
High Beam Relay B+22
Headlamp Flash to Pass Signal444
Headlamp Dimmer Switch Signal444
Headlamp Low Beam Control111
Headlamp Low Beam Relay Control11B2575 00
Headlamp Switch Off ControlB257A 0033
Headlamp Switch On ControlB257A 0033
Headlamp High Beam Control222
Headlamp High Beam Relay Control22B2580 00
Headlamp Switch Ground3
Turn Signal/Multifunction Switch Malfunction4
1. Headlamp Malfunction - Low Beam 2. Headlamp Malfunction - High Beam 3. Headlamp Switch Malfunction 4. Dimmer Switch Malfunction

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

Schematic Reference

  1. «Headlights/Daytime Running Lights (DRL) Schematics»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system)
  2. «Exterior Lights Schematics»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system)

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition ON, observe the scan tool Headlamp Switch parameter while turning the headlamp switch ON and OFF. The reading should change between Active and Inactive. If the reading does not change between the specified values, refer to Headlamp Switch Malfunction in «Circuit/System Testing»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) .
  2. Observe the scan tool Auto Hdlp. Disable Sw. parameter while turning the headlamp switch ON and OFF. The reading should toggle between Active and Inactive. If the reading does not change between the specified values, refer to Headlamp Switch Malfunction in «Circuit/System Testing»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) .
  3. Observe the scan tool Flash to Pass Switch parameter while applying and releasing the turn signal/multifunction switch. The reading should toggle between Active and Inactive. If the reading does not change between the specified values, refer to Turn Signal/Multifunction Switch Malfunction in «Circuit/System Testing»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) .
  4. Observe the scan tool High Beam Select Switch parameter while applying and releasing the high beam select switch. The reading should toggle between Active and Inactive. If the reading does not change between the specified values, refer to Turn Signal/Multifunction Switch Malfunction in «Circuit/System Testing»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) .
  5. Command the Low Beams ON and OFF with a scan tool. The low beam headlamps should turn ON and OFF when commanded. If the low beam headlamps do not turn ON and OFF when commanded, refer to Headlamps Malfunction - Low Beam in «Circuit/System Testing»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) .
  6. Command the DRLs ON and OFF with a scan tool. The daytime running lamps should turn ON and OFF when commanded. If the low beam headlamps do not turn ON and OFF when commanded, refer to Headlamps Malfunction - Daytime Running Lamps in «Circuit/System Testing»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) .
  7. Command the High Beams ON and OFF with a scan tool. The high beam headlamps should turn ON and OFF when commanded. If the high beam headlamps do not turn ON and OFF when commanded, refer to Headlamps Malfunction - High Beam in «Circuit/System Testing»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) .
  8. Command the Lamp Test ON and OFF with a scan tool. The lights on indicator and high beam indicator should turn ON and OFF when changing between the commanded states. If the lights on indicator and high beam indicator illuminate during the test, replace the BCM. If the lights on indicator and high beam indicator do not illuminate during the test or remain illuminated at all times, replace the instrument cluster.
WARNINGThe high intensity discharge system produces high voltage and current. To reduce the risk of severe shocks and burns: Never open the high intensity discharge system ballast or the arc tube assembly starter. Never probe between the high intensity discharge system ballast output connector and the arc tube assembly.

Headlamp Switch Malfunction

  1. Ignition OFF, disconnect the harness connector at the headlamp and panel dimmer switch.
  2. Ignition OFF, verify that a test lamp illuminates between B+ and the ground circuit terminal 8. If the test lamp does not illuminate, test the ground circuit for an open/high resistance.
  3. Ignition ON, verify the scan tool Headlamp Switch parameter is Inactive. If not the specified value, test the signal circuit terminal 1 for a short to ground. If the circuit tests normal, replace the BCM.
  4. Verify the scan tool Auto Hdlp. Disable Sw. parameter is Inactive. If not the specified value, test the signal circuit terminal 3 for a short to ground. If the circuit tests normal, replace the BCM.
  5. Install a 3 A fused jumper wire between the signal circuit terminal 1 and ground. Verify the scan tool Headlamp Switch parameter is Active. If not the specified value, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the BCM.
  6. Install a 3 A fused jumper wire between the signal circuit terminal 3 and ground. Verify the scan tool Auto Hdlp. Disable Sw. parameter is Active. If not the specified value, test the signal circuit for a short to voltage or and open/high resistance. If the circuit tests normal, replace the BCM.
  7. If all circuits test normal, test or replace the headlamp and panel dimmer switch.

Turn Signal/Multifunction Switch Malfunction

  1. Ignition OFF, disconnect the X2 harness connector at the turn signal/multifunction switch.
  2. Ignition OFF, verify that a test lamp illuminates between B+ and the ground circuit terminal D. If greater than the specified range, test the ground circuit for an open/high resistance.
  3. Ignition ON, verify the scan tool Flash to Pass Switch parameter is Inactive. If not the specified value, test the signal circuit terminal A for a short to ground. If the circuit tests normal, replace the BCM.
  4. Verify the scan tool High Beam Select Switch parameter is Inactive. If not the specified value, test the signal circuit terminal E for a short to ground. If the circuit tests normal, replace the BCM.
  5. Install a 3 A fused jumper wire between the signal circuit terminal A and ground. Verify the scan tool Flash to Pass Switch parameter is Active. If not the specified value, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the BCM.
  6. Install a 3 A fused jumper wire between the signal circuit terminal E and ground. Verify the scan tool High Beam Select Switch parameter is Active. If not the specified value, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the BCM.
  7. If all circuits test normal, test or replace the turn signal/multifunction switch.

Headlamps Malfunction - Low Beam (with X88, Z88 and Z75)

  1. Ignition OFF, disconnect the HDLP LO/HID relay.
  2. Ignition ON, verify that a test lamp does not illuminate between the control circuit terminal 87 and ground. If the test lamp illuminates, test the control circuit for a short to voltage.
  3. Verify that a test lamp illuminates between the B+ circuit terminal 85 and ground. If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.
  4. Verify that a test lamp illuminates between the B+ circuit terminal 30 and ground. If the test lamp does not illuminate, test the B+ circuit for an open/high resistance.
  5. Disconnect the harness connector at the appropriate headlamp.
  6. Test for less than 5 ohms between the headlamp ground circuit terminal listed below and ground: RPO X88 - terminal A RPO Z88 - terminal B RPO Z75 - terminal 2 If greater than the specified range, test the ground circuit for an open/high resistance.
  7. Connect the harness connector at the headlamp.
  8. Connect a 20 A fused jumper wire between the B+ circuit terminal 30 and the control circuit terminal 87. Verify the headlamp - low beam is activated. If the headlamp - low beam does not activate and the circuit fuse is good, test the control circuit for an open/high resistance. If the circuit tests normal, test or replace the headlamp. If the headlamp - low beam does not activate and the circuit fuse is open, test the control circuit for a short to ground. If the circuit tests normal, test or replace the headlamp.
  9. Connect a test lamp between the B+ circuit terminal 85 and the control circuit terminal 86.
  10. Command the Low Beams ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states. If the test lamp is always ON, test the control circuit for a short to ground. If the circuit tests normal, replace the BCM. If the test lamp is always OFF, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the BCM.
  11. If all circuits test normal, test or replace the HDLP LO/HID relay.

Headlamps Malfunction - Daytime Running Lamps (with X88 and Z75)

  1. Ignition OFF, disconnect the X4 harness connector at the fuse block - underhood.
  2. Connect a test lamp between the control circuit terminal H4 and B+.
  3. Command the DRL ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states. If the test lamp is always ON, test the control circuit for a short to ground. If the circuit tests normal, replace the BCM. If the test lamp is always OFF, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the BCM.
  4. Ignition OFF, connect the X4 harness connector at the fuse block - underhood. Disconnect the harness connector at the appropriate daytime running lamp.
  5. Test for less than 5 ohms between the daytime running lamp ground circuit terminal listed below and ground: RPO X88 - terminal C RPO Z75 - terminal B If greater than the specified range, test the ground circuit for an open/high resistance.
  6. Connect a test lamp between the control circuit terminal A and ground.
  7. Command the DRL ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states. If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the fuse block - underhood. If the test lamp is always OFF and the circuit fuse is good, test the control circuit for an open/high resistance. If the circuit tests normal, test or replace the fuse block - underhood. If the test lamp is always OFF and the circuit fuse is open, test the control circuit for a short to ground. If the circuit tests normal, test or replace the daytime running lamp.
  8. If all circuits test normal, test or replace the daytime running lamp.

Headlamps Malfunction - High Beam (with X88, Z88 and Z75)

  1. Ignition OFF, disconnect the X4 harness connector at the fuse block - underhood.
  2. Connect a test lamp between the control circuit terminal C3 and B+.
  3. Command the High Beams ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states. If the test lamp is always ON, test the control circuit for a short to ground. If the circuit tests normal, replace the BCM. If the test lamp is always OFF, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the BCM.
  4. Ignition OFF, connect the X4 harness connector at the fuse block - underhood. Disconnect the harness connector at the appropriate headlamp.
  5. Test for less than 5 ohms between the headlamp ground circuit terminal listed below and ground: RPO X88 - terminal A RPO Z88 - terminal B RPO Z75 - terminal 1 If greater than the specified range, test the ground circuit for an open/high resistance.
  6. Connect a test lamp between the control circuit terminal listed below and ground: RPO X88 - terminal B RPO Z88 - terminal C RPO Z75 - terminal 2
  7. Command the High Beams ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states. If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the fuse block - underhood. If the test lamp is always OFF and the circuit fuse is good, test the control circuit for an open/high resistance. If the circuit tests normal, test or replace the fuse block - underhood. If the test lamp is always OFF and the circuit fuse is open, test the control circuit for a short to ground. If the circuit tests normal, test or replace the headlamp.
  8. If all circuits test normal, test or replace the headlamp.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Headlamp Bulb Replacement (Cadillac)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) or «Headlamp Bulb Replacement (Tahoe, Avalanche)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) or «Headlamp Bulb Replacement (Yukon)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system)
  2. «Headlamp Switch Replacement (Cadillac)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) or «Headlamp Switch Replacement (Except Cadillac)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system)
  3. «Relay Replacement (Attached to Wire Harness)»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-repair-instructions) or «Relay Replacement (Within an Electrical Center)»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-repair-instructions)
  4. «Headlamp Replacement (Cadillac Escalade)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) or «Headlamp Replacement (GMC Yukon Two-mode Hybrid)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) or «Headlamp Replacement (Yukon)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) or «Headlamp Replacement (Chevrolet Tahoe Two-mode Hybrid)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) or «Headlamp Replacement (Tahoe, Avalanche)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) or «Headlamp Replacement (Escalade PLATINUM)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) or «Headlamp Replacement (Non HID)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system)
  5. «Headlamp Ballast Replacement»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system)
  6. «Underhood Electrical Center or Junction Block Replacement»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-repair-instructions)
  7. «Turn Signal Multifunction Switch Replacement»(/cadillac/escalade/gmt900-2006-2014/remont/steering-column-switches/#steering-wheel-steering-column)
  8. «Control Module References»(/cadillac/escalade/gmt900-2006-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM or instrument panel replacement, setup, and programming
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Headlamp LO/HID Relay B+11
High Beam Relay B+22
Headlamp Flash to Pass Signal444
Headlamp Dimmer Switch Signal444
Headlamp Outage Detection Signal - Left555
Headlamp Outage Detection Signal - Right555
Headlamp Low Beam Control111
Headlamp Low Beam Relay Control11B2575 00
Headlamp Switch Off ControlB257A 0033
Headlamp Switch On ControlB257A 0033
Headlamp High Beam Control222
Headlamp High Beam Relay Control22B2580 00
Headlamp Switch Ground3
Turn Signal/Multifunction Switch Malfunction4
1. Headlamp Malfunction - Low Beam 2. Headlamp Malfunction - High Beam 3. Headlamp Switch Malfunction 4. Dimmer Switch Malfunction 5. Headlamp Outage Detection Malfunction

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

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

Schematic Reference

  1. «Headlights/Daytime Running Lights (DRL) Schematics»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system)
  2. «Exterior Lights Schematics»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system)

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition ON, observe the scan tool Headlamp Switch parameter while turning the headlamp switch ON and OFF. The reading should change between Active and Inactive. If the reading does not change between the specified values, refer to Headlamp Switch Malfunction in «Circuit/System Testing»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) .
  2. Observe the scan tool Auto Hdlp. Disable Sw. parameter while turning the headlamp switch ON and OFF. The reading should toggle between Active and Inactive. If the reading does not change between the specified values, refer to Headlamp Switch Malfunction in «Circuit/System Testing»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) .
  3. Observe the scan tool Flash to Pass Switch parameter while applying and releasing the turn signal/multifunction switch. The reading should toggle between Active and Inactive. If the reading does not change between the specified values, refer to Turn Signal/Multifunction Switch Malfunction in «Circuit/System Testing»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) .
  4. Observe the scan tool High Beam Select Switch parameter while applying and releasing the high beam select switch. The reading should toggle between Active and Inactive. If the reading does not change between the specified values, refer to Turn Signal/Multifunction Switch Malfunction in «Circuit/System Testing»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) .
  5. Command the Low Beams ON and OFF with a scan tool. The low beam headlamps should turn ON and OFF when commanded. If the low beam headlamps do not turn ON and OFF when commanded, refer to Headlamps Malfunction - Low Beam in «Circuit/System Testing»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) .
  6. Command the High Beams ON and OFF with a scan tool. The high beam headlamps should turn ON and OFF when commanded. If the high beam headlamps do not turn ON and OFF when commanded, refer to Headlamps Malfunction - High Beam in «Circuit/System Testing»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) .
  7. Observe the low beam, high beam, park and marker lamp LEDs at each headlamp assembly. All LEDs should illuminate when commanded ON If all LEDs illuminate when commanded and the Service Headlamp Assembly indicator is ON, refer to Headlamp Outage Detection Malfunction in «Circuit/System Testing»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) .
  8. Command the Lamp Test ON and OFF with a scan tool. The lights on indicator, high beam indicator and service headlamp assembly indicator should turn ON and OFF when changing between the commanded states. If the lights on indicator, high beam indicator and service headlamp assembly indicator illuminate during the test, replace the BCM. If the lights on indicator, high beam indicator and service headlamp assembly indicator do not illuminate during the test or remain illuminated at all times, replace the instrument cluster.

Headlamp Switch Malfunction

  1. Ignition OFF, disconnect the harness connector at the headlamp and panel dimmer switch.
  2. Ignition OFF, verify that a test lamp illuminates between B+ and the ground circuit terminal 8. If the test lamp does not illuminate, test the ground circuit for an open/high resistance.
  3. Ignition ON, verify the scan tool Headlamp Switch parameter is Inactive. If not the specified value, test the signal circuit terminal 1 for a short to ground. If the circuit tests normal, replace the BCM.
  4. Verify the scan tool Auto Hdlp. Disable Sw. parameter is Inactive. If not the specified value, test the signal circuit terminal 3 for a short to ground. If the circuit tests normal, replace the BCM.
  5. Install a 3 A fused jumper wire between the signal circuit terminal 1 and ground. Verify the scan tool Headlamp Switch parameter is Active. If not the specified value, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the BCM.
  6. Install a 3 A fused jumper wire between the signal circuit terminal 3 and ground. Verify the scan tool Auto Hdlp. Disable Sw. parameter is Active. If not the specified value, test the signal circuit for a short to voltage or and open/high resistance. If the circuit tests normal, replace the BCM.
  7. If all circuits test normal, test or replace the headlamp and panel dimmer switch.

Turn Signal/Multifunction Switch Malfunction

  1. Ignition OFF, disconnect the X2 harness connector at the turn signal/multifunction switch.
  2. Ignition OFF, verify that a test lamp illuminates between B+ and the ground circuit terminal D. If greater than the specified range, test the ground circuit for an open/high resistance.
  3. Ignition ON, verify the scan tool Flash to Pass Switch parameter is Inactive. If not the specified value, test the signal circuit terminal A for a short to ground. If the circuit tests normal, replace the BCM.
  4. Verify the scan tool High Beam Select Switch parameter is Inactive. If not the specified value, test the signal circuit terminal E for a short to ground. If the circuit tests normal, replace the BCM.
  5. Install a 3 A fused jumper wire between the signal circuit terminal A and ground. Verify the scan tool Flash to Pass Switch parameter is Active. If not the specified value, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the BCM.
  6. Install a 3 A fused jumper wire between the signal circuit terminal E and ground. Verify the scan tool High Beam Select Switch parameter is Active. If not the specified value, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the BCM.
  7. If all circuits test normal, test or replace the turn signal/multifunction switch.

Headlamps Malfunction - Low Beam

  1. Ignition OFF, disconnect the HDLP LO/HID relay.
  2. Ignition ON, verify that a test lamp does not illuminate between the control circuit terminal 87 and ground. If the test lamp illuminates, test the control circuit for a short to voltage.
  3. Verify that a test lamp illuminates between the B+ circuit terminal 85 and ground. If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.
  4. Verify that a test lamp illuminates between the B+ circuit terminal 30 and ground. If the test lamp does not illuminate, test the B+ circuit for an open/high resistance.
  5. Connect a test lamp between the B+ circuit terminal 85 and the control circuit terminal 86.
  6. Command the Low Beams ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states. If the test lamp is always ON, test the control circuit for a short to ground. If the circuit tests normal, replace the BCM. If the test lamp is always OFF, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the BCM.
  7. Ignition OFF, connect the HDLP LO/HID relay.
  8. Disconnect the harness connector at the appropriate headlamp.
  9. Ignition OFF, scan tool OFF, exterior lamps OFF, test for less than 5.0 ohms between each ground circuit terminal listed below and ground. Ground circuit terminal F Ground circuit terminal M If greater than the specified range, test the ground circuit for an open/high resistance.
  10. Connect a test lamp between the control circuit terminal A and ground.
  11. Command the Low Beams ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states. If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the HDLP LO/HID relay. If the test lamp is always OFF, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the HDLP LO/HID relay.
  12. Ignition OFF, connect the harness connector at the headlamp.
  13. Command the Low Beams ON and OFF with a scan tool. The low beam headlamp should turn ON and OFF when changing between the commanded states. If all of the low beam LED's do not illuminate, replace the headlamp control module. If some of the low beam LEDs illuminate, replace the headlamp assembly.

Headlamps Malfunction - High Beam

  1. Ignition OFF, disconnect the X4 connector at the underhood fuse block.
  2. Connect a test lamp between the control circuit terminal C3 and B+.
  3. Ignition ON, command the High Beams ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states. If the test lamp is always ON, test the control circuit for a short to ground. If the circuit tests normal, replace the BCM. If the test lamp is always OFF, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the BCM.
  4. Ignition OFF, disconnect the harness connector at the appropriate headlamp.
  5. Ignition OFF, scan tool OFF, exterior lamps OFF, test for less than 5.0 ohms between each ground circuit terminal listed below and ground. Ground circuit terminal F Ground circuit terminal M If greater than the specified range, test the ground circuit for an open/high resistance.
  6. Connect a test lamp between the control circuit terminal L and ground.
  7. Command the High Beams ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states. If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the underhood fuse block. If the test lamp is always OFF, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the underhood fuse block.
  8. Ignition OFF, connect the harness connector at the headlamp.
  9. Command the High Beams ON and OFF with a scan tool. The high beam headlamp should turn ON and OFF when changing between the commanded states. If all of the high beam LED's do not illuminate, replace the headlamp control module. If some of the high beam LEDs illuminate, replace the headlamp assembly.

Headlamp Outage Detection Malfunction

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

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Headlamp Replacement (Cadillac Escalade)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) or «Headlamp Replacement (GMC Yukon Two-mode Hybrid)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) or «Headlamp Replacement (Yukon)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) or «Headlamp Replacement (Chevrolet Tahoe Two-mode Hybrid)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) or «Headlamp Replacement (Tahoe, Avalanche)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) or «Headlamp Replacement (Escalade PLATINUM)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) or «Headlamp Replacement (Non HID)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system)
  2. «Headlamp Control Module Replacement (Escalade PLATINUM)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system)
  3. «Headlamp Ballast Replacement»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system)
  4. «Headlamp Switch Replacement (Cadillac)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) or «Headlamp Switch Replacement (Except Cadillac)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system)
  5. «Relay Replacement (Attached to Wire Harness)»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-repair-instructions) or «Relay Replacement (Within an Electrical Center)»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-repair-instructions)
  6. «Turn Signal Multifunction Switch Replacement»(/cadillac/escalade/gmt900-2006-2014/remont/steering-column-switches/#steering-wheel-steering-column)
  7. «Underhood Electrical Center or Junction Block Replacement»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-repair-instructions)
  8. «Control Module References»(/cadillac/escalade/gmt900-2006-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM, instrument panel or headlamp control module replacement, setup, and programming
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
I/P Dimming Voltage ReferenceB1395 03B1395 03B1395 07
Courtesy Lamp Voltage ReferenceB2615 00, B2615 02B2615 00, B2615 04B2615 00, B2615 01
LED Indicator Dimming Volage ReferenceB2625 00B2625 00B2625 00
Dome/Reading Lamp ControlB2615 00B2615 00
Dome/Reading Lamp Supply Voltage11
Dome Lamp Switch Signal222
Exterior Lamps Illumination Supply Voltage555
Inadvertent Power Control555
I/P Lamps Dimming ControlB2652 00B2652 00B2652 00
Left Front Door Open Switch Signal333
Left Rear Door Open Switch Signal444
Right Front Door Open Switch Signal333
Right Rear Door Open Switch Signal444
Dome/Reading Lamp Low Control - Driver Door1
Dome/Reading Lamp Low Control - Passenger Door1
Exterior Lamps Low Reference5
I/P Dimmer Switch Ground2
LH Vanity Mirror Courtesy Lamp Ground1
Overhead Console Courtesy Lamp Ground1
Rear Dome Lamp Ground1
RH Vanity Mirror Courtesy Lamp Ground1
1. Courtesy Lamps Malfunction 2. Dome Lamp Switch Malfunction 3. Door Open Switch Malfunction - Front 4. Door Open Switch Malfunction - Rear 5. Exterior Lamps Malfunction

When the ignition switch is turned to the RUN position, the radio vacuum fluorescent display turns ON at maximum brightness. When the park lamps are ON, all incandescent and LED back lighting turn ON at the dimming level indicated by the instrument panel (I/P) dimmer switch. At the same time all vacuum fluorescent displays dim to match the indicated dimming level. The panel dimmer switch potentiometer is an input to the body control module (BCM). When the driver selects a dimming setting by moving the I/P dimming switch potentiometer, all incandescent back lighting lamps are provided with a specific voltage. When the I/P dimmer switch is moved from MIN to MAX, all vacuum fluorescent displays, as well as all incandescent back lighting respond from minimum intensity to maximum brightness in response to the I/P dimmer switch

Schematic Reference

  1. «Interior Lights Dimming Schematics»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system)
  2. «Interior Lights Schematics»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system)

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition ON, observe the scan tool Dimming Control Signal parameter while operating the dimmer switch from high to low. The reading should change from a high percent to a low percent as the switch is activated. If the reading does not change, refer to Dimmer Switch Malfunction in «Circuit/System Testing»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) .
  2. Observe the function of the backlighting components while commanding the LED Dimming or Incandescent Dimming ON and OFF with a scan tool. The backlighting components should turn ON and OFF while changing between the commanded states. If the backlighting components do not turn ON and OFF, refer to Interior Backlighting Malfunction in «Circuit/System Testing»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) .
  3. Observe the driver door switch while commanding the Integrated Sw. Backlighting Test ON and OFF with a scan tool. The driver door switch backlighting should turn ON and OFF when changing between the commanded states. If the driver door switch backlighting does not operate as described, replace the driver door lock and side window switch.
  4. Observe the driver memory/heated seat switch while commanding the Non-Integrated Backlighting Test ON and OFF with a scan tool. The driver memory/heated seat switch backlighting should turn ON and OFF when changing between the commanded states. If the driver memory/heated seat switch backlighting does not operate as described, refer to Front Door Switch Backlighting Malfunction in «Circuit/System Testing»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) .
  5. Observe the passenger door switch while commanding the Integrated Sw. Backlighting Test ON and OFF with a scan tool. The passenger door switch backlighting should turn ON and OFF when changing between the commanded states. If the passenger door switch backlighting does not operate as described, replace the passenger door lock and side window switch.
  6. Observe the passenger memory/heated seat switch while commanding the Non-Integrated Backlighting Test ON and OFF with a scan tool. The passenger memory/heated seat switch backlighting should turn ON and OFF when changing between the commanded states. If the passenger memory/heated seat switch backlighting does not operate as described, refer to Front Door Switch Backlighting Malfunction in «Circuit/System Testing»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) .

Dimmer Switch Malfunction

  1. Ignition OFF, disconnect the harness connector at the headlamp and panel dimmer switch.
  2. Ignition OFF, verify that a test lamp illuminates between the ground circuit terminal 8 and B+. If the test lamp does not illuminate, test the ground circuit for an open/high resistance.
  3. Ignition ON, verify the scan tool Dimming Control Signal parameter is less than 0.1 V. If greater than the specified range, test the signal circuit terminal 13 for a short to voltage. If the circuit tests normal, replace the BCM.
  4. Ignition ON, test for B+ between the I/P dimming voltage reference circuit terminal 15 and ground. If less than the specified value, test the voltage reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM.
  5. Install a 3 A fused jumper wire between the signal circuit terminal 13 and the voltage reference circuit terminal 15. Verify the scan tool BCM Dimming Control Signal parameter is greater than 2.6 V. If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM.
  6. If all circuits test normal, test or replace the headlamp and panel dimmer switch.

Interior Backlighting Malfunction

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

Front Door Switch Backlighting Malfunction

  1. Ignition OFF, disconnect the harness connector X4 at the door lock and side window switch.
  2. Connect a 3 A fused jumper wire between the low reference circuit terminal 4 and ground.
  3. Connect a test lamp between the backlight supply voltage circuit terminal 13 and B+. The heated seat switch backlighting should illuminate. If the switch backlighting does not illuminate, replace the heated seat switch.
  4. If the switch backlighting tests normal, replace the door lock and side window switch.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Front Seat Heater Switch Replacement»(/cadillac/escalade/gmt900-2006-2014/remont/seats/#seat-heating-system-seat-cooling-system)
  2. «Steering Wheel Control Switch Assembly Replacement»(/cadillac/escalade/gmt900-2006-2014/remont/memory-modules/#configurable-customer-control-system)
  3. «Driver Information Display Switch Replacement (Except Cadillac)»(/cadillac/escalade/gmt900-2006-2014/remont/gauges-instrument-panels/#instrument-panel-system-displays-gauges) or «Driver Information Display Switch Replacement (Cadillac)»(/cadillac/escalade/gmt900-2006-2014/remont/gauges-instrument-panels/#instrument-panel-system-displays-gauges)
  4. «Accessory Switch Replacement (Except Cadillac)»(/cadillac/escalade/gmt900-2006-2014/remont/gauges-instrument-panels/#instrument-panel-system-displays-gauges) or «Accessory Switch Replacement (Cadillac)»(/cadillac/escalade/gmt900-2006-2014/remont/gauges-instrument-panels/#instrument-panel-system-displays-gauges)
  5. «Headlamp Switch Replacement (Cadillac)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) or «Headlamp Switch Replacement (Except Cadillac)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system)
  6. «Door Lock and Side Window Switch Replacement - Driver Side»(/cadillac/escalade/gmt900-2006-2014/remont/door-locks-anti-theft-systems/#door-lock-system-door-handles)
  7. «Door Lock and Side Window Switch Replacement - Passenger Side»(/cadillac/escalade/gmt900-2006-2014/remont/door-locks-anti-theft-systems/#door-lock-system-door-handles)
  8. «Control Module References»(/cadillac/escalade/gmt900-2006-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM, door lock and side window switch, IPC, radio, HVAC control module, and rear seat audio controller replacement, setup, and programming
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Park Lamp Relay B+11
Park Lamp Switch Signal222
Park Lamp Relay Control11B2585 00
Park Lamp Control111
Park Lamp Ground1
Headlamp and Panel Dimmer Switch Ground1
1. Park, License, and/or Tail Lamps Malfunction 2. Park Lamp Switch Malfunction

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

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition ON, observe the scan tool Parking Lamp Switch parameter while cycling the park lamp switch ON and OFF. The readings should toggle between Active and Inactive. If the readings do not change between the commanded states, refer to Park Lamp Switch Malfunction in «Circuit/System Testing»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) .
  2. Ignition ON, command the Parking Lamps ON and OFF with a scan tool. The park lamps should turn ON and OFF when changing between the commanded states. If the park lamps do not turn ON and OFF when commanded, refer to Park, License, and/or Tail Lamps Malfunction in «Circuit/System Testing»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) .

Park Lamp Switch Malfunction

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

Park, License, and/or Tail Lamps Malfunction

  1. Ignition OFF, disconnect the park lamp relay.
  2. Ignition ON, verify that a test lamp does not illuminate between the control circuit terminal 87 and ground. If the test lamp illuminates, test the control circuit for a short to voltage.
  3. Verify that a test lamp illuminates between the B+ circuit terminal 86 and ground. If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance. If the circuit tests normal and the B+ circuit fuse is open, test the control circuit terminal 87 for a short to ground. If the circuit tests normal, test or replace the park lamp relay.
  4. Verify that a test lamp illuminates between the B+ circuit terminal 30 and ground. If the test lamp does not illuminate, test the B+ circuit for an open/high resistance.
  5. Disconnect the harness connector at the appropriate park/license/marker lamp.
  6. Ignition OFF, exterior lamps OFF, test for less than 5 ohms between the appropriate ground circuit terminal listed below and ground. Park/Turn Signal Lamp - Left or Right front terminal C - with X88 Park/Turn Signal Lamp - Left or Right front terminal G - with Z88 Marker Lamp - Left or Right front terminal A - with Z75 Marker Lamp - Left or Right front terminal B - with Z88 or X88 Park Lamp - Left or Right front terminal B - Z75 Tail/Stop and Turn Signal Lamp - Lower Left or Right rear terminal G - w/o X88 - E52 Tail/Stop and Turn Signal Lamp - Upper Left or Right rear terminal GND - with X88 - E52 Tail/Turn Signal Lamp - Left or Right terminal G - w/o X88 + E52 Tail/Turn Signal Lamp - Left or Right terminal GND - with X88 + E52 Tail/Stop Lamp - Left or Right Rear terminal G - w/o X88 + E52 Tail/Stop Lamp - Left or Right Rear terminal GND - w/o X88 + E52 Marker Lamp - Left or Right Rear terminal B - with Z88 Marker Lamp - Left or Right Rear terminal A - with Z75 or X88 - E52 Tail Lamp Circuit Board - Left or Right Rear terminal D - with Z75 + E52 License lamp terminal B If greater than the specified range, test the ground circuit for an open/high resistance.
  7. Connect the harness connector at the park/license/marker lamp.
  8. Connect a 15 A fused jumper wire between the B+ circuit terminal 30 and the control circuit terminal 87. Verify the park/marker lamps illuminate. If the park/marker lamps do not illuminate, test the control circuit for an open/high resistance. If the circuit tests normal, replace the inoperative park/license/marker lamp.
  9. Connect a test lamp between the control circuit terminal 85 and B+ circuit terminal 86.
  10. Command the Parking Lamps ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states. If the test lamp is always ON, test the control circuit for a short to ground. If the circuit tests normal, replace the BCM. If the test lamp is always OFF, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the BCM.
  11. If all circuits test normal, test or replace the park lamp relay.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Parking and Turn Signal Lamp Bulb Replacement (Yukon)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system__parking-and-turn-signal-lamp-bulb) or «Parking and Turn Signal Lamp Bulb Replacement (Escalade)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) or «Parking and Turn Signal Lamp Bulb Replacement (Cadillac)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) or «Parking and Turn Signal Lamp Bulb Replacement (Tahoe, Avalanche)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system__parking-and-turn-signal-lamp-bulb)
  2. «Rear License Plate Lamp Replacement (GMC Denali)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) or «Rear License Plate Lamp Replacement (Escalade)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) or «Rear License Plate Lamp Replacement (Yukon Two-mode Hybrid)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system)
  3. «Tail Lamp Bulb Replacement (Yukon)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) or «Tail Lamp Bulb Replacement (Cadillac)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system__tail-lamp-bulb-replacement-cadillac) or «Tail Lamp Bulb Replacement (Tahoe, Avalanche)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) or «Tail Lamp Bulb Replacement (Tahoe)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) or «Tail Lamp Bulb Replacement (Yukon Two-mode Hybrid)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system)
  4. «Headlamp Switch Replacement (Cadillac)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) or «Headlamp Switch Replacement (Except Cadillac)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system)
  5. «Front Side Marker Lamp Replacement (Yukon)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) or «Front Side Marker Lamp Replacement (Tahoe, Avalanche)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system)
  6. «Parking and Turn Signal Lamp Replacement (Tahoe, Avalanche)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) or «Parking and Turn Signal Lamp Replacement (Yukon)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system)
  7. «Tail Lamp Replacement (Avalanche)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) or «Tail Lamp Replacement (GMC Yukon Two-Mode Hybrid)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) or «Tail Lamp Replacement (Chevrolet Tahoe Two-Mode Hybrid)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system__tail-lamp-replacement-chevrolet-tahoe-two-mode) or «Tail Lamp Replacement (Cadillac)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system__tail-lamp-replacement-cadillac) or «Tail Lamp Replacement (Tahoe, Yukon)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system)
  8. «Relay Replacement (Attached to Wire Harness)»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-repair-instructions) or «Relay Replacement (Within an Electrical Center)»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-repair-instructions)
  9. «Control Module References»(/cadillac/escalade/gmt900-2006-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM replacement, setup, and programming
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Park Lamp Relay B+11
Park Lamp Switch Signal222
Park Lamp Relay Control11B2585 00
Park Lamp Control111
Park Lamp Ground1
Headlamp and Panel Dimmer Switch Ground1
1. Park, License, and/or Tail Lamps Malfunction 2. Park Lamp Switch Malfunction

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

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition ON, observe the scan tool Parking Lamp Switch parameter while cycling the park lamp switch ON and OFF. The readings should toggle between Active and Inactive. If the readings do not change between the commanded states, refer to Park Lamp Switch Malfunction in «Circuit/System Testing»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) .
  2. Command the Parking Lamps ON and OFF with a scan tool. The park lamps should turn ON and OFF when changing between the commanded states. If the park lamps do not turn ON and OFF when commanded, refer to Park, License, and/or Tail Lamps Malfunction in «Circuit/System Testing»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) .
  3. Command the Parking Lamps ON and OFF with a scan tool. The front LED park lamps should turn ON and OFF when changing between the commanded states. If the front LED park lamps do not turn ON and OFF when commanded, refer to Front LED Park Lamps Malfunction in «Circuit/System Testing»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) .

Park Lamp Switch Malfunction

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

Park, License, and/or Tail Lamps Malfunction

  1. Ignition OFF, disconnect the park lamp relay.
  2. Ignition ON, verify that a test lamp does not illuminate between the control circuit terminal 87 and ground. If the test lamp illuminates, test the control circuit for a short to voltage.
  3. Verify that a test lamp illuminates between the B+ circuit terminal 86 and ground. If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance. If the circuit tests normal and the B+ circuit fuse is open, test the control circuit terminal 87 for a short to ground. If the circuit tests normal, test or replace the park lamp relay.
  4. Verify that a test lamp illuminates between the B+ circuit terminal 30 and ground. If the test lamp does not illuminate, test the B+ circuit for an open/high resistance.
  5. Disconnect the harness connector at the appropriate park/license/marker lamp.
  6. Ignition OFF, exterior lamps OFF, test for less than 5 ohms between the appropriate ground circuit terminal listed below and ground. Headlamp - Left or Right terminal J Tail Lamp Circuit Board - Left or Right Rear terminal D - with Z75 + E52 License lamp terminal B If greater than the specified range, test the ground circuit for an open/high resistance.
  7. Connect the harness connector at the park/license/marker lamp.
  8. Connect a 15 A fused jumper wire between the B+ circuit terminal 30 and the control circuit terminal 87. Verify the park/marker lamps illuminate. If the park/marker lamps do not illuminate, test the control circuit for an open/high resistance. If the circuit tests normal, replace the park/license/marker lamp.
  9. Connect a test lamp between the control circuit terminal 85 and B+ circuit terminal 86.
  10. Command the Parking Lamps ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states. If the test lamp is always ON, test the control circuit for a short to ground. If the circuit tests normal, replace the BCM. If the test lamp is always OFF, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the BCM.
  11. If all circuits test normal, test or replace the park lamp relay.

Front LED Park Lamps Malfunction

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

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Headlamp Switch Replacement (Cadillac)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) or «Headlamp Switch Replacement (Except Cadillac)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system)
  2. «Headlamp Replacement (Cadillac Escalade)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) or «Headlamp Replacement (GMC Yukon Two-mode Hybrid)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) or «Headlamp Replacement (Yukon)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) or «Headlamp Replacement (Chevrolet Tahoe Two-mode Hybrid)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) or «Headlamp Replacement (Tahoe, Avalanche)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) or «Headlamp Replacement (Escalade PLATINUM)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) or «Headlamp Replacement (Non HID)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system)
  3. «Parking and Turn Signal Lamp Replacement (Tahoe, Avalanche)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) or «Parking and Turn Signal Lamp Replacement (Yukon)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system)
  4. «Rear License Plate Lamp Replacement (GMC Denali)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) or «Rear License Plate Lamp Replacement (Escalade)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) or «Rear License Plate Lamp Replacement (Yukon Two-mode Hybrid)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system)
  5. «Tail Lamp Replacement (Avalanche)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) or «Tail Lamp Replacement (GMC Yukon Two-Mode Hybrid)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) or «Tail Lamp Replacement (Chevrolet Tahoe Two-Mode Hybrid)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system__tail-lamp-replacement-chevrolet-tahoe-two-mode) or «Tail Lamp Replacement (Cadillac)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system__tail-lamp-replacement-cadillac) or «Tail Lamp Replacement (Tahoe, Yukon)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system)
  6. «Relay Replacement (Attached to Wire Harness)»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-repair-instructions) or «Relay Replacement (Within an Electrical Center)»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-repair-instructions)
  7. «Control Module References»(/cadillac/escalade/gmt900-2006-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM or headlamp control module replacement, setup, and programming
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
MISC IGN Fuse B+ Supply11
Stop Lamp Switch 12 V ReferenceB3445 003
STOP LAMPS Fuse B+ Supply11
Left Outage Detection Signal111
Left Outage Detection Signal - European444
Right Outage Detection Signal111
Right Outage Detection Signal - European444
Stop Lamp Switch Signal33
Stop Lamp Switch Control111
Center High Mounted Stop Lamp ControlB3884 0022
Left Lower Tail/Stop and Turn Signal Lamp Control111
Left Upper Tail/Stop and Turn Lamp Control111
Left Tail Lamp Control Circuit Board Control111
Left Tail Lamp Control Circuit Board Control - European444
Right Lower Tail/Stop and Turn Signal Lamp Control111
Right Upper Tail/Stop and Turn Signal Lamp Control111
Right Tail Lamp Control Circuit Board Control111
Right Tail Lamp Control Circuit Board Control - European444
Center High Mounted Stop Lamp Ground2
Left Upper Tail/Stop and Turn Signal Lamp Ground1
Left Tail Lamp Control Circuit Board Ground1
Left Lower Tail/Stop and Turn Signal Lamp Ground1
Left Tail/Stop Lamp Ground1
Left Tail Lamp Circuit Board Ground - European4
Right Lower Tail/Stop and Turn Signal Lamp Ground1
Right Lower Tail/Stop and Turn Signal Lamp Ground1
Right Tail Lamp Control Circuit Board Ground1
Right Tail/Stop Lamp Ground1
Right Tail Lamp Circuit Board - European4
1. Stop Lamps Malfunction - North American 2. Center High Mounted Stop Lamp (CHMSL) Malfunction 3. Stop Lamp Switch Malfunction 4. Stop Lamps Malfunction - European

The stop lamp switch is used to sense the action of the driver application of the brake pedal. The body control module (BCM) provides a low reference signal and a B+ reference voltage to the stop lamp switch. When the stop lamp switch contacts close indicating the brakes have been applied, the BCM will apply battery voltage to stop lamp relay control circuit and the center high mounted stop lamp (CHMSL). When the stop lamp relay receives battery voltage from the BCM, the relay coil is energized and the stop lamp relay switch contacts close applying battery voltage to the STOP LAMPS fuse to illuminate the left and right stop lamps.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition ON, observe the scan tool Stop Lamp Relay Command parameter while pressing and releasing the brake pedal. The parameter should change between ON and OFF. If the parameter does not change between the commanded states, refer to the Stop Lamp Switch Malfunction in «Circuit/System Testing»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) .
  2. Observe the left and right stop lamps while pressing and releasing the brake pedal. The stop lamps should turn ON and OFF. If the left or right stop lamps do not change between the selected states, refer to the Stop Lamp Malfunction in «Circuit/System Testing»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) .
  3. Observe the center high mount stop lamp while pressing and releasing the brake pedal. The center high mount stop lamp should turn ON and OFF. If the center high mount stop lamp does not change between the selected states, refer to Center High Mount Stop Lamp Malfunction in «Circuit/System Testing»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) .

Stop Lamp Switch Malfunction

  1. Ignition OFF, disconnect the harness connector at the stop lamp switch.
  2. Ignition ON, test for battery voltage between the 12 V reference circuit terminal C and ground. If less than the specified range, test the 12 V reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM.
  3. Verify the scan tool Stop Lamp Switch Status parameter is approximately 1023 counts. If not the specified value, test the signal circuit terminal D for a short to voltage. If the circuit tests normal, replace the BCM.
  4. Install a 3 A fused jumper wire between the signal circuit terminal D and the 12 V reference circuit terminal C. Verify the scan tool Stop Lamp Switch Status parameter is 1 count. If not the specified value, test the signal circuit for an open/high resistance. If the circuit tests normal, replace the BCM.
  5. If all circuits test normal, test or replace the stop lamp switch.

Stop Lamp Malfunction

  1. Ignition OFF, disconnect the harness connector X4 at the BCM.
  2. Ignition ON, verify a test lamp illuminates between the stop lamp B+ terminal 4 and ground. If the test lamp does not illuminate, and the STOP LAMPS fuse tests normal, test the B+ circuit for a short to ground or an open/high resistance.
  3. Connect the harness connector X4 at the BCM.
  4. Ignition OFF, disconnect the harness connector at the appropriate stop lamp.
  5. Test for less than 5.0 ohms between the listed ground circuit terminal below and ground. Tail/Stop and Turn Signal Lamp - Left and Right - Upper and Lower terminal GRD - with Z75 - E52 Tail Lamp Circuit Board - Left and Right terminal D - with Z75 + E52 and European Tail/Stop Lamp - Left and Right terminal GRD - with X88 Tail/Stop Lamp - Left and Right terminal G - Z88 Tail/Stop Lamp - Left and Right terminal 2 - with HP2 If greater than the specified range, test the ground circuit for an open/high resistance.
  6. Connect a test lamp between the stop lamp control circuit terminal listed below and ground circuit terminal. Tail/Stop and Turn Signal Lamp - Left and Right - Upper and Lower terminal MJR - with Z75 - E52 Tail Lamp Circuit Board - Left and Right terminal E - with Z75 + E52 and European Tail/Stop Lamp - Left and Right terminal MJR - with X88 Tail/Stop Lamp - Left and Right terminal A - Z88 Tail/Stop Lamp - Left and Right terminal 1 - with HP2
  7. Ignition ON, press and release the brake pedal. The test lamp should turn ON and OFF when changing between the selected states. If the test lamp is always ON, test the control circuit for a short to voltage. If the test lamp is always OFF, test the control circuit for a short to ground or an open/high resistance.
  8. If all circuits test normal, test or replace the stop lamp.

Center High Mount Stop Lamp Malfunction

  1. Ignition OFF, disconnect the harness connector X4 at the BCM.
  2. Ignition ON, verify a test lamp illuminates between the B+ circuit terminal 4 and ground. If the test lamp does not illuminate, test the B+ circuit for an open/high resistance or short to ground.
  3. Reconnect the harness connector X4 at the BCM.
  4. Ignition OFF, disconnect the harness connector at the center high mounted stop lamp.
  5. Test for less than 5.0 ohms between the ground circuit terminal B and ground. If greater than the specified range, test the ground circuit for an open/high resistance.
  6. Connect a test lamp between the stop lamp control circuit terminal A and ground circuit terminal B.
  7. Ignition ON, press and release the brake pedal. The test lamp should turn ON and OFF when changing between the selected states. If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the BCM. If the test lamp is always OFF, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM.
  8. If all circuits test normal, test or replace the center high mount stop lamp.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Stop Lamp Switch Replacement (With Adjustable Pedals)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) or «Stop Lamp Switch Replacement (Without Adjustable Pedals)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system)
  2. «High Mount Stop Lamp Replacement (Yukon Two-mode Hybrid)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) or «High Mount Stop Lamp Replacement (Yukon)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) or «High Mount Stop Lamp Replacement (Avalanche)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) or «High Mount Stop Lamp Replacement (Escalade)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system)
  3. «Tail Lamp Bulb Replacement (Yukon)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) or «Tail Lamp Bulb Replacement (Cadillac)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system__tail-lamp-bulb-replacement-cadillac) or «Tail Lamp Bulb Replacement (Tahoe, Avalanche)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) or «Tail Lamp Bulb Replacement (Tahoe)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) or «Tail Lamp Bulb Replacement (Yukon Two-mode Hybrid)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system)
  4. «Tail Lamp Replacement (Avalanche)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) or «Tail Lamp Replacement (GMC Yukon Two-Mode Hybrid)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) or «Tail Lamp Replacement (Chevrolet Tahoe Two-Mode Hybrid)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system__tail-lamp-replacement-chevrolet-tahoe-two-mode) or «Tail Lamp Replacement (Cadillac)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system__tail-lamp-replacement-cadillac) or «Tail Lamp Replacement (Tahoe, Yukon)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system)
  5. «Control Module References»(/cadillac/escalade/gmt900-2006-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM replacement, setup, and programming
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
LT Stop TRN Fuse B+ Supply11
RT Stop TRN Fuse B+ Supply11
Hazard Switch Signal222
Turn Signal Switch Signal - Left333
Turn Signal Switch Signal - Right333
Turn Signal Lamp Control - LF111
Turn Lamp Control - LR111
Turn Signal Lamp Control - RF111
Turn Lamp Control - RR111
Hazard Switch Ground2
Lower Stop/Turn Lamp Ground - RR1
Lower Stop/Turn Lamp Ground - LR1
Park/Turn Signal Lamp - LF1
Park/Turn Signal Lamp - RF1
Repeater Lamp Ground - RF1
Repeater Lamp Ground - LF1
Turn Signal/Multifunction Switch Ground3
Turn Signal Lamp - LF Ground1
Turn Signal Lamp - RF Ground1
Upper Stop/Turn Lamp Ground - LR1
Upper Stop/Turn Lamp Ground - RR1
1. Turn Signal Lamps and/or Indicators Malfunction 2. Hazard Lamps Malfunction 3. Turn Signal Switch Malfunction

When the turn signal switch is placed in either the left or right position, a ground signal is completed from the turn signal switch to the BCM. When the hazard flasher switch is activated, a ground signal is completed from the turn signal/hazard switch to the BCM. The BCM then sends a pulsating voltage signal through the fuses to the appropriate turn signal and side repeater (European only) lamps or to all of the turn signal fuses for hazard operation. The driver door switch and passenger door switch also receive voltage from the BCM turn signal supply voltage circuits for the mirror turn signals. The door switches have no function or control of the mirror turn signals other than a pass through connection for the circuits. The audio chime is also activated when the turn signals are ON. The instrument panel cluster (IPC) receives the signals to activate the turn signal indicators over the GMLAN serial data system.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition ON, observe the scan tool Right Turn Signal Switch and Left Turn Signal Switch parameters while cycling the turn signal switch between the right and left positions. The readings should change between Active and Inactive. If the parameters do not change between the selected states, refer to Turn Signal Switch Malfunction in «Circuit/System Testing»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) .
  2. Ignition ON, observe the right and left turn signal lamps while cycling the turn signal switch between the right and left positions. Verify the turn signal lamps turn ON and OFF. If the turn signal lamps do not cycle between the selected states, refer to Turn Signal Lamp Malfunction in «Circuit/System Testing»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) .
  3. Command the Lamp Test ON and OFF with a scan tool. The left and right turn signal indicators should turn ON and OFF when changing between the commanded states. If the left and right turn signal indicators illuminate during the test, replace the BCM. If the left and right turn signal indicators do not illuminate during the test or remain illuminated at all times, replace the instrument cluster.

Turn Signal Switch Malfunction

  1. Ignition OFF, disconnect the harness connector X1 at the turn signal/multifunction switch.
  2. Ignition OFF, verify that a test lamp illuminates between B+ and the ground circuit terminal F. If the test lamp does not illuminate, test the ground circuit for an open/high resistance.
  3. Ignition ON, verify the scan tool Left Front and Rear Turn Signal Switch parameter is INACTIVE. If not the specified value, test the signal circuit terminal E for a short to ground. If the circuit tests normal, replace the BCM.
  4. Verify the scan tool Right Front and Rear Turn Signal Switch parameter is INACTIVE. If not the specified value, test the signal circuit terminal D for a short to ground. If the circuit tests normal, replace the BCM.
  5. Verify the scan tool Hazard Lamp Switch parameter is INACTIVE. If not the specified value, test the signal circuit terminal G for a short to ground. If the circuit tests normal, replace the BCM.
  6. Install a 3 A fused jumper wire between the signal circuit terminal E and ground. Verify the scan tool Left Turn Signal Switch parameter is ACTIVE. If not the specified value, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the BCM.
  7. Install a 3 A fused jumper wire between the signal circuit terminal D and ground. Verify the scan tool Right Turn Signal Switch parameter is ACTIVE. If not the specified value, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the BCM.
  8. Install a 3 A fused jumper wire between the signal circuit terminal G and ground. Verify the scan tool Hazard Lamp Switch parameter is ACTIVE. If not the specified value, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the BCM.
  9. If all circuits test normal, test or replace the turn signal/multifunction switch.

Turn Signal Lamp Malfunction

  1. Ignition OFF, disconnect the X4 harness connector at the BCM.
  2. Verify that a test lamp illuminates between the LT STOP TRN fuse B+ circuit terminal 1 and ground. If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.
  3. Verify that a test lamp illuminates between the RT STOP TRN fuse B+ circuit terminal 3 and ground. If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.
  4. Ignition OFF, reconnect the X4 harness connector at the BCM.
  5. Disconnect the harness connector at the appropriate turn signal lamp.
  6. Test for less than 5.0 ohms between the ground circuit terminal and ground. Park/Turn Signal Lamp - Left front terminal C - with X88/Z88 Park/Turn Signal Lamp - Right front terminal A - with X88/Z88 Turn Signal Lamp - Left and Right front terminal 3- with Z75 Repeater Lamp - Left and Right front terminal 2 - with TR2 Tail/Turn Signal Lamp - Left and Right rear terminal GRD - with X88 Tail/Turn Signal Lamp - Left and Right rear terminal G- w/o X88 Tail/Stop and Turn Signal Lamp - Left and Right Upper rear terminal GRD - with X88/Z75 - EXP - E52 Tail/Stop and Turn Signal Lamp - Left and Right Lower rear terminal GRD - with X88/Z75 - EXP - E52 Tail Lamp Circuit Board - Left and Right rear terminal D - with Z75 + E52 If greater than the specified range, test the ground circuit for an open/high resistance.
  7. Connect a test lamp between the appropriate turn signal control circuit terminal and ground. Park/Turn Signal Lamp - Left front terminal A - with X88/Z88 Park/Turn Signal Lamp - Right front terminal D - with X88/Z88 Turn Signal Lamp - Left and Right front terminal 1- with Z75 Repeater Lamp - Left and Right front terminal 1- with TR2 Tail/Turn Signal Lamp - Left and Right rear terminal MJR - with X88 Tail/Turn Signal Lamp - Left and Right rear terminal A - w/o X88 Tail/Stop and Turn Signal Lamp - Left and Right Upper rear terminal MJR - with X88/Z75 - EXP - E52 Tail/Stop and Turn Signal Lamp - Left and Right Lower rear terminal MJR - with X88/Z75 - EXP - E52 Tail Lamp Circuit Board - Left and Right rear terminal B - with Z75 + E52 - with EXP Tail Lamp Circuit Board - Left and Right rear terminal E - with Z75 + E52 - w/o EXP
  8. Ignition ON, command the appropriate turn signal ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states. If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the BCM. If the test lamp is always OFF, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM.
  9. If all circuits test normal, test or replace the appropriate turn signal lamp.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Parking and Turn Signal Lamp Bulb Replacement (Yukon)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system__parking-and-turn-signal-lamp-bulb) or «Parking and Turn Signal Lamp Bulb Replacement (Escalade)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) or «Parking and Turn Signal Lamp Bulb Replacement (Cadillac)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) or «Parking and Turn Signal Lamp Bulb Replacement (Tahoe, Avalanche)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system__parking-and-turn-signal-lamp-bulb)
  2. «Tail Lamp Bulb Replacement (Yukon)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) or «Tail Lamp Bulb Replacement (Cadillac)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system__tail-lamp-bulb-replacement-cadillac) or «Tail Lamp Bulb Replacement (Tahoe, Avalanche)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) or «Tail Lamp Bulb Replacement (Tahoe)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) or «Tail Lamp Bulb Replacement (Yukon Two-mode Hybrid)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system)
  3. «Turn Signal Multifunction Switch Replacement»(/cadillac/escalade/gmt900-2006-2014/remont/steering-column-switches/#steering-wheel-steering-column)
  4. «Tail Lamp Replacement (Avalanche)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) or «Tail Lamp Replacement (GMC Yukon Two-Mode Hybrid)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) or «Tail Lamp Replacement (Chevrolet Tahoe Two-Mode Hybrid)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system__tail-lamp-replacement-chevrolet-tahoe-two-mode) or «Tail Lamp Replacement (Cadillac)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system__tail-lamp-replacement-cadillac) or «Tail Lamp Replacement (Tahoe, Yukon)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system)
  5. «Parking and Turn Signal Lamp Replacement (Tahoe, Avalanche)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system) or «Parking and Turn Signal Lamp Replacement (Yukon)»(/cadillac/escalade/gmt900-2006-2014/remont/exterior-lights/#lighting-system)
  6. «Control Module References»(/cadillac/escalade/gmt900-2006-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM or IPC replacement, setup, and programming

Removal Procedure

  1. Apply the park brake.
  2. Remove the driver knee bolster. Refer to «Knee Bolster Replacement (Cadillac)»(/cadillac/escalade/gmt900-2006-2014/remont/exteriorinterior-trim/#instrument-panel-trim-and-console-trim) or «Knee Bolster Replacement (Except Cadillac)»(/cadillac/escalade/gmt900-2006-2014/remont/exteriorinterior-trim/#instrument-panel-trim-and-console-trim) .
  3. Disconnect the stoplamp switch electrical connector.
  4. Remove the power vacuum brake booster pushrod retainer bolt (1).
  5. Remove the power vacuum brake booster pushrod retainer (1).
  6. Slide the power vacuum brake booster pushrod off of the brake pedal pin and remove the stoplamp switch (1).

Installation Procedure

  1. Install the stoplamp switch (1) to the power vacuum brake booster pushrod.
  2. Install the power vacuum brake booster pushrod with the stoplamp switch to the brake pedal pin.
  3. Install the power vacuum brake booster pushrod retainer (1).
  4. Rotate the pushrod retainer 360 degrees to verify the retainer is fully engaged in the groove on the brake pedal pin.
  5. Install the power vacuum brake booster pushrod retainer bolt (1) and tighten to 10 N.m (89 lb in).
  6. Connect the stoplamp switch electrical connector.
  7. Install the driver knee bolster. Refer to «Knee Bolster Replacement (Cadillac)»(/cadillac/escalade/gmt900-2006-2014/remont/exteriorinterior-trim/#instrument-panel-trim-and-console-trim) or «Knee Bolster Replacement (Except Cadillac)»(/cadillac/escalade/gmt900-2006-2014/remont/exteriorinterior-trim/#instrument-panel-trim-and-console-trim) .

Scheme 26

Scheme 26: Stop Lamp Switch Replacement (Without Adjustable Pedals)
Scheme 26: Stop Lamp Switch Replacement (Without Adjustable Pedals)
CalloutComponent Name
Preliminary Procedures Apply the park brake. Remove the driver knee bolster. Refer to Knee Bolster Replacement (Cadillac) or Knee Bolster Replacement (Except Cadillac) . Disconnect the stoplamp switch electrical connector.
1Power Vacuum Brake Booster Pushrod Retainer Bolt CAUTION: Refer to Fastener Caution . Tighten: 10 N.m (89 lb in)
2Power Vacuum Brake Booster Pushrod Retainer Procedure: Rotate the pushrod retainer 360 degrees to verify the retainer is fully engaged in the groove on the brake pedal pin.
3Stoplamp Switch
CAUTION
Refer to Fastener Caution .
  1. Remove the driver knee bolster. Refer to «Knee Bolster Replacement (Cadillac)»(/cadillac/escalade/gmt900-2006-2014/remont/exteriorinterior-trim/#instrument-panel-trim-and-console-trim) or «Knee Bolster Replacement (Except Cadillac)»(/cadillac/escalade/gmt900-2006-2014/remont/exteriorinterior-trim/#instrument-panel-trim-and-console-trim) .
  2. Remove the fuse block cover.
  3. Disconnect the brake pedal position sensor electrical connector (1).
  4. Remove the brake pedal position sensor bolts (2).
  5. Remove the brake pedal position sensor (3) from the vehicle.
  1. Install the brake pedal position sensor (3) to the vehicle.
  2. Install the brake pedal position sensor bolts (2) and tighten to 9 N.m (80 lb in).
  3. Connect the brake pedal position sensor electrical connector (1).
  4. Install the fuse block cover.
  5. Install the driver knee bolster. Refer to «Knee Bolster Replacement (Cadillac)»(/cadillac/escalade/gmt900-2006-2014/remont/exteriorinterior-trim/#instrument-panel-trim-and-console-trim) or «Knee Bolster Replacement (Except Cadillac)»(/cadillac/escalade/gmt900-2006-2014/remont/exteriorinterior-trim/#instrument-panel-trim-and-console-trim) .

Scheme 27

Scheme 27: Headlamp Switch Replacement (Cadillac)
Scheme 27: Headlamp Switch Replacement (Cadillac)
CalloutComponent Name
1Headlamp Switch Bezel Assembly Refer to Headlamp Switch Bezel Replacement (Except Cadillac) or Headlamp Switch Bezel Replacement (Cadillac) .
2Headlamp Switch Assembly

Scheme 28

Scheme 28: Headlamp Switch Replacement (Except Cadillac)
Scheme 28: Headlamp Switch Replacement (Except Cadillac)
CalloutComponent Name
1Headlamp Switch Bezel Assembly Procedure Use the trim tool to unsnap the switch from the bezel. Disconnect the electrical connector.
2Headlamp Switch Assembly Procedure: Unsnap the switch from the bezel.

Fog Lamp Switch Replacement

CalloutComponent Name
Fastener Tightening Specifications: Refer to Fastener Tightening Specifications .
1Headlamp Switch Trim Plate Assembly Refer to Headlamp Switch Bezel Replacement (Except Cadillac) or Headlamp Switch Bezel Replacement (Cadillac) .
2Headlamp and I/P Lamp Dimmer and Dome Lamp Switch Assembly Tip: Fog lamp switch is an integral part of the headlamp switch and the unit must therefore be replaced in whole.

Scheme 29

Scheme 29: Ambient Light Sensor Replacement
Scheme 29: Ambient Light Sensor Replacement
CalloutComponent Name
1Instrument Panel Trim Panel Refer to Instrument Panel Upper Trim Panel with Windshield Defroster Nozzle Grille Replacement (Except Cadillac) or Instrument Panel Upper Trim Panel with Windshield Defroster Nozzle Grille Replacement (Cadillac) .
2Headlamp Auto Control Ambient Light Sensor Assembly Procedure Twist and pull down to remove. Disconnect the electrical connector.

Scheme 30

Scheme 30: Dome and Reading Lamp Bulb Replacement (Overhead Console)
Scheme 30: Dome and Reading Lamp Bulb Replacement (Overhead Console)
CalloutComponent Name
Fastener Tightening Specifications: Refer to Fastener Tightening Specifications .
1Dome Lamp Lens
2Dome Lamp Bulb (Qty: 2)

Scheme 31

Scheme 31: Dome and Reading Lamp Bulb Replacement (Dome Lamp)
Scheme 31: Dome and Reading Lamp Bulb Replacement (Dome Lamp)
CalloutComponent Name
Fastener Tightening Specifications: Refer to Fastener Tightening Specifications .
1Dome Lamp Lens
2Dome Lamp Bulb (Qty: 2)

Scheme 32

Scheme 32: Outside Rearview Mirror Courtesy Lamp Replacement
Scheme 32: Outside Rearview Mirror Courtesy Lamp Replacement
CalloutComponent Name
Fastener Tightening Specifications: Refer to Fastener Tightening Specifications .
1Exterior Courtesy Lamp Assembly Tip: Use a flat-bladed tool to pry off assembly starting at end closest to door. Tilt assembly end and pull down to release. Disconnect electrical connector.
2Exterior Courtesy Lamp Socket Tip: Twist and pull to release.
3Exterior Courtesy Lamp Bulb

Scheme 33

Scheme 33: Door Courtesy Lamp and Reflector Replacement
Scheme 33: Door Courtesy Lamp and Reflector Replacement
CalloutComponent Name
Fastener Tightening Specifications: Refer to Fastener Tightening Specifications .
1Door Courtesy Lamp/Reflector Assembly Tip: Gently push assembly toward front edge of door. Lift rear of assembly from door using a small flat-bladed tool. Remove courtesy lamp/reflector from door panel.

Scheme 34

Scheme 34: Dome Lamp Replacement
Scheme 34: Dome Lamp Replacement
CalloutComponent Name
Fastener Tightening Specifications: Refer to Fastener Tightening Specifications .
1Dome Lamp Lens Tip: Using a flat-bladed tool pry down on right side of lens to avoid damaging tab.
2Dome Lamp Housing Tip: Disconnect electrical connector.

Scheme 35

Scheme 35: Headlamp Replacement (Cadillac Escalade)
Scheme 35: Headlamp Replacement (Cadillac Escalade)
CalloutComponent Name
Preliminary Procedures Remove the 2 forward wheelhouse liner screws. Remove the 3 washer container push pins. Open the hood. Through the wheelhouse opening, loosen the lower headlamp bolt (1). Remove the 2 upper headlamp bolts. Grasp the headlamp at the upper inboard and lower outboard side and pull the headlamp forward to disengage from the snap feature. Pull the outboard side of the headlamp forward until the locating pins disengage from the radiator support. Disconnect the electrical harness connector.
1Headlamp Lower Screw CAUTION: Refer to Fastener Caution . Tighten: 6 N.m (53 lb in)
2Headlamp Screw (Qty: 2) Tighten: 6 N.m (53 lb in)
3Headlamp Bracket Tip: Pull to release the headlamp tab from the bracket.
4Forward Lamp Harness Electrical Connector
5Headlamp Assembly
CAUTION
Refer to Fastener Caution .

Scheme 36

Scheme 36: Headlamp Replacement (GMC Yukon Two-mode Hybrid)
Scheme 36: Headlamp Replacement (GMC Yukon Two-mode Hybrid)
CalloutComponent Name
Preliminary Procedures Remove the 2 forward wheelhouse liner retainers. Remove the 2 washer container push pins. Open the hood. Remove the 6 upper fascia bolts right to the hood latch mechanism. Remove the lower rear fascia bolt from the support bracket. Loosen the 2 fascia to fender bolts from under the fascia. Pull the outboard end of the front fascia straight outboard until it disengages from the fender attachment bracket. Pull the fascia forward and downward to allow enough clearance to remove the headlamp assembly. Loosen the lower outboard attachment bolts. Remove the 2 upper headlamp bolts. Grasp the headlamp at the upper inboard and lower outboard side and pull the headlamp forward to disengage the locating tab. Pull the outboard side of the headlamp forward until the 2 locating pins disengage from the radiator support. Disconnect the forward lamp harness connector.
1Headlamp Bolt (Qty: 2) CAUTION: Refer to Fastener Caution . Tip: Secure the headlamp using the sequence as listed. Tighten: 6 N.m (53 lb in)
2Headlamp Bolt Tip: Loosen the lower outer fender bolt but do not remove. Tighten: 6 N.m (53 lb in)
3Headlamp Assembly Procedure Upon assembly, align the 2 outer locating pins and one inner alignment tab to the radiator support prior to applying pressure to the lamp in order to seat the lamp. Aim the headlamp assembly. Refer to Headlamp Aiming (Tahoe/Yukon) or Headlamp Aiming (Escalade) .
CAUTION
Refer to Fastener Caution .

Scheme 37

Scheme 37: Headlamp Replacement (Yukon)
Scheme 37: Headlamp Replacement (Yukon)
CalloutComponent Name
Preliminary Procedures Remove the 2 forward wheelhouse liner screws. Remove the 2 washer container push pins. Open the hood. Remove the 6 upper fascia bolts right to the hood latch mechanism. Remove the lower rear fascia bolt from the support bracket. Loosen the 2 fascia to fender bolts from under the fascia. Pull the outboard end of the front fascia straight outboard until it disengages from the fender attachment bracket. Pull the fascia forward and downward to allow enough clearance to remove the headlamp assembly. Loosen the lower outboard attachment bolts. Remove the 2 upper headlamp bolts. Grasp the headlamp at the upper inboard and lower outboard side and pull the headlamp forward to disengage the locating tab. Pull the outboard side of the headlamp forward until the 2 locating pins disengage from the radiator support. Disconnect the forward lamp harness connector.
1Headlamp Bolt (Qty: 2) CAUTION: Refer to Fastener Caution . Tip: Secure the headlamp using the sequence as listed. Tighten: 6 N.m (53 lb in)
2Headlamp Bolt Tip: Loosen the lower outer fender bolt but do not remove. Tighten: 6 N.m (53 lb in)
3Headlamp Assembly Tip: Upon assembly, align the 2 outer locating pins and one inner alignment tab to the radiator support prior to applying pressure to the lamp in order to seat the lamp.
CAUTION
Refer to Fastener Caution .

Scheme 38

Scheme 38: Headlamp Replacement (Chevrolet Tahoe Two-mode Hybrid)
Scheme 38: Headlamp Replacement (Chevrolet Tahoe Two-mode Hybrid)
CalloutComponent Name
Preliminary Procedures Remove the front bumper fascia. Refer to Front Bumper Fascia Replacement (Avalanche) or Front Bumper Fascia Replacement (Yukon) or Front Bumper Fascia Replacement (Escalade) or Front Bumper Fascia Replacement (Tahoe) or Front Bumper Fascia Replacement (Z71) . Remove the 2 upper headlamp bolts. Grasp the headlamp at the upper inboard and lower outboard side and pull the headlamp forward to disengage the locating pins from the fender panel. Pull the outboard side of the headlamp forward until the locating pin is disengaged from the radiator support. Disconnect the electrical harness connector.
1Headlamp Bolt CAUTION: Refer to Fastener Caution . Tighten: 6 N.m (53 lb in)
2Headlamp Bolt Tighten: 6 N.m (53 lb in)
3Forward Lamp Harness Electrical Connector
4Headlamp Assembly Procedure Upon re-assembly, align the locating tab along with the outer locating pins prior to applying inward pressure to the headlamp assembly. Aim the headlamp assembly. Refer to Headlamp Aiming (Tahoe/Yukon) or Headlamp Aiming (Escalade) .
CAUTION
Refer to Fastener Caution .

Scheme 39

Scheme 39: Headlamp Replacement (Tahoe, Avalanche)
Scheme 39: Headlamp Replacement (Tahoe, Avalanche)
CalloutComponent Name
Preliminary Procedures Remove the 2 forward wheelhouse liner screws in order to access the hidden lower headlamp bolt. Refer to Front Wheelhouse Liner Replacement - Left Side or Front Wheelhouse Liner Replacement - Right Side . Open the hood. Remove the upper fascia bolts. Remove the lower rear fascia bolt from the support bracket. Loosen the 2 fascia to fender bolts from behind the wheelhouse liner. Pull the outboard end of the front fascia straight outboard until it disengages from the fender attachment bracket. Pull the fascia forward and downward to allow enough clearance to remove the headlamp assembly. Remove the 2 upper headlamp bolts. Grasp the headlamp at the upper inboard and lower outboard side and pull the headlamp forward to disengage the locating pins from the fender panel. Pull the outboard side of the headlamp forward until the locating pin is disengaged from the radiator support. Disconnect the electrical harness connector.
1Headlamp Bolt CAUTION: Refer to Fastener Caution . Tighten: 6 N.m (53 lb in)
2Headlamp Bolt Tighten: 6 N.m (53 lb in)
3Forward Lamp Harness Electrical Connector
4Headlamp Assembly Tip: Upon re-assembly, align the locating tab along with the outer locating pins prior to applying inward pressure to the headlamp assembly.
CAUTION
Refer to Fastener Caution .

Scheme 40

Scheme 40: Headlamp Replacement (Escalade PLATINUM)
Scheme 40: Headlamp Replacement (Escalade PLATINUM)
CalloutComponent Name
Preliminary Procedures Remove the 2 forward wheelhouse liner screws. Remove the 3 washer container push pins. Open the hood. Through the wheelhouse opening, loosen the lower headlamp bolt (1) but do not remove. Remove the 2 upper headlamp bolts. Grasp the headlamp at the upper inboard and lower outboard side and pull the headlamp forward to disengage from the lower radiator support bracket. Pull the outboard side of the headlamp forward until the locating pins disengage from the radiator support. Disconnect the forward lamp electrical harness connector from the headlamp control module.
1Headlamp Lower Screw CAUTION: Refer to Fastener Caution . Tighten: 6 N.m (53 lb in)
2Headlamp Screw (Qty: 2) Tighten: 6 N.m (53 lb in)
3Headlamp Support Bracket Tip: Pull to release the headlamp tab from the bracket on the radiator support.
4Forward Lamp Harness Electrical Connector
5Headlamp Assembly Tip: The headlamp assembly is light emitting diode (LED). The only part serviceable is the ELC module, transfer the module as needed upon headlamp replacement.
CAUTION
Refer to Fastener Caution .

Scheme 41

Scheme 41: Headlamp Replacement (Non HID)
Scheme 41: Headlamp Replacement (Non HID)
CalloutComponent Name
Preliminary Procedures Remove the 2 forward screws (1). Remove the 2 wheelhouse to washer container pushpins, LH only. Open the hood. Remove the underhood beauty pane, Cadillac only. Remove the 6 upper fascia/grille bolts all the way to latch. Remove the lower rear fascia bolt from the support bracket. Loosen the 2 fascia to fender bolts from the bottom of fascia. Pull the outboard end of the front fascia straight outboard until it disengages from the fender attachment bracket. Pull the fascia forward and downward to allow enough clearance to remove the headlamp assembly. Remove the cross-car lower outboard headlamp attachment bolt. Remove the 2 remaining upper headlamp attachment bolts. Loosen the cross-car lower outboard headlamps attachment bolts. Grasp the headlamp at the upper inboard and lower outboard corners and pull the lamp straight forward until it disengages from the snap feature. Pull the outboard side of the headlamp forward until the locating pins disengage from the fender. Rock and cam the headlamp out of the vehicle. Disconnect the electrical harness connector.
1Headlamp Screw (Qty: 2) CAUTION: Refer to Fastener Caution . Tighten: 6 N.m (53 lb in)
2Headlamp Screw Tighten: 6 N.m (53 lb in)
3Headlamp Assembly Alignment Tab (Qty: 2) Tip: Pull to release the tabs on the back of the headlamp assembly.
4Headlamp Assembly Tip: Disconnect the electrical connectors.
CAUTION
Refer to Fastener Caution .

Scheme 42

Scheme 42: Headlamp Ballast Replacement
Scheme 42: Headlamp Ballast Replacement
CalloutComponent Name
Preliminary Procedure: Remove the headlamp. Refer to Headlamp Replacement (Cadillac Escalade) or Headlamp Replacement (GMC Yukon Two-mode Hybrid) or Headlamp Replacement (Yukon) or Headlamp Replacement (Chevrolet Tahoe Two-mode Hybrid) or Headlamp Replacement (Tahoe, Avalanche) or Headlamp Replacement (Escalade PLATINUM) or Headlamp Replacement (Non HID) .
1Headlamp Ballast Assembly Screw (Qty: 3) CAUTION: Refer to Fastener Caution . Tighten: 2 N.m (18 lb in)
2Headlamp Ballast Assembly
CAUTION
Refer to Fastener Caution .

Scheme 43

Scheme 43: Headlamp Bulb Replacement (Cadillac)
Scheme 43: Headlamp Bulb Replacement (Cadillac)
CalloutComponent Name
Preliminary Procedure: Remove the headlamp. Refer to Headlamp Replacement (Cadillac Escalade) or Headlamp Replacement (Escalade PLATINUM) or Headlamp Replacement (Non HID) .
1Headlamp Bulb Assembly Access Cover
2Headlamp Bulb Assembly
3Headlamp Bulb Connector

Scheme 44

Scheme 44: Headlamp Bulb Replacement (Tahoe, Avalanche)
Scheme 44: Headlamp Bulb Replacement (Tahoe, Avalanche)
CalloutComponent Name
Preliminary Procedure: Remove the headlamp. Refer to Headlamp Replacement (Chevrolet Tahoe Two-mode Hybrid) or Headlamp Replacement (Tahoe, Avalanche) .
1Low Beam Bulb
2High Beam Bulb

Scheme 45

Scheme 45: Headlamp Bulb Replacement (Yukon)
Scheme 45: Headlamp Bulb Replacement (Yukon)
CalloutComponent Name
Preliminary Procedure: Remove the headlamp. Refer to Headlamp Replacement (GMC Yukon Two-mode Hybrid) or Headlamp Replacement (Yukon) .
1High Low Beam Bulb

Headlamp Aiming (Tahoe/Yukon)

Headlamp aiming is done with the low beam lamps. The high beam lamps will be correctly aimed if the low beam lamps are aimed properly.

Screen Method for Headlamp Aiming (Visual Aim)

The screen method requires an area set up specifically for headlamp aim.

Scheme 46

Scheme 46: Screen Method for Headlamp Aiming (Visual Aim)
Scheme 46: Screen Method for Headlamp Aiming (Visual Aim)

The area should consist of a level surface large enough to allow for a vehicle and an additional 7.62 m (25 ft) as measured from the face of the headlamps to the aiming screen.

The screen should be a wall or other flat surface at least 1.52 m (5 ft) high by 3.66 m (12 ft) wide with a matte white surface well shaded from extraneous light, and 90 degrees to the floor (a). The screen should be provided with a permanent vertical reference line 0.61 m (2 ft) from the left edge of the screen, 2 laterally adjustable vertical tapes, and one vertically adjustable horizontal tape.

After the aiming screen has been set up and located, paint or tape a reference line on the floor 15.24 m (50 ft) from the vertical reference line on the screen. This line should be perpendicular to the aiming screen and a mark placed at 7.62 m (25 ft) from the screen.

Headlamp Aiming Procedure

  1. Align the left tires of the vehicle with the reference line extending from the screen with the headlamps aligned with the reference line.
  2. Remove any snow, ice or mud from the vehicle.
  3. The vehicle should be fully assembled and all other work stopped while the headlamp aiming is being done.
  4. The vehicle should contain cargo or be loaded to represent normal vehicle use.
  5. Tires should be properly inflated.
  6. Rock the vehicle to stabilize the suspension.
  7. Measure from the floor to the center of the lamp bulb on the vehicle. Some lamps have an aim dot marked on the lens.
  8. At the screen, measure from the floor and place the horizontal tape at the measured distance.
  9. Measure from the reference line on the floor to the left headlamp bulb centerline (1).
  10. At the screen, measure from the reference line and place the vertical tape at the measured distance (2).
  11. Measure from the reference line on the floor to the right headlamp bulb centerline.
  12. At the screen, measure from the reference line and place the vertical tape at the measured distance.
  13. Turn the headlamps ON.
  14. Block the light from projecting onto the screen from the passenger side headlamp. This will allow the cutoff in the beam pattern from the drivers side to be more pronounced for easier aim verification.
  15. On this vehicle you will be verifying the aim of the vertical cutoff on the right side of the lamp vertical bulb centerline as it is projected onto the aim board.
  16. If the location of the cutoff projected onto the board differs from (Scheme 4) then an adjustment to the beam pattern location is necessary.
  17. Adjust the vertical headlamp adjustment screw until the Right Gradient Line (Cutoff Line) is set at the Horizontal Axis within +/- 2.0 inches (2) measured at 25feet.
  18. Verify proper aim location.
  19. Repeat the aiming procedure for the passengers side headlamp while blocking the light from projecting onto the screen from the drivers side headlamp.

Headlamp Aiming (Escalade)

Headlamp aiming is done with the low beam lamps. The high beam lamps will be correctly aimed if the low beam lamps are aimed properly.

The screen method requires an area set up specifically for headlamp aim.

The area should consist of a level surface large enough to allow for a vehicle and an additional 7.62 m (25 ft) as measured from the face of the headlamps to the aiming screen.

The screen should be a wall or other flat surface at least 1.52 m (5 ft) high by 3.66 m (12 ft) wide with a matte white surface well shaded from extraneous light, and 90 degrees to the floor (a). The screen should be provided with a permanent vertical reference line 0.61 m (2 ft) from the left edge of the screen, 2 laterally adjustable vertical tapes, and one vertically adjustable horizontal tape.

After the aiming screen has been set up and located, paint or tape a reference line on the floor 15.24 m (50 ft) from the vertical reference line on the screen. This line should be perpendicular to the aiming screen and a mark placed at 7.62 m (25 ft) from the screen.

  1. Align the left tires of the vehicle with the reference line extending from the screen with the headlamps aligned with the reference line.
  2. Remove any snow, ice or mud from the vehicle.
  3. The vehicle should be fully assembled and all other work stopped while the headlamp aiming is being done.
  4. The vehicle should contain cargo or be loaded to represent normal vehicle use.
  5. Tires should be properly inflated.
  6. Rock the vehicle to stabilize the suspension.
  7. Measure from the floor to the center of the lamp bulb on the vehicle. Some lamps have an aim dot marked on the lens.
  8. At the screen, measure from the floor and place the horizontal tape at the measured distance.
  9. Measure from the reference line on the floor to the left headlamp bulb centerline (1).
  10. At the screen, measure from the reference line and place the vertical tape at the measured distance.
  11. Measure from the reference line on the floor to the right headlamp bulb centerline (3).
  12. At the screen, measure from the reference line and place the vertical tape at the measured distance.
  13. Turn the headlamps ON.
  14. Block the light from projecting onto the screen from the passenger side headlamp. This will allow the cutoff in the beam pattern from the drivers side to be more pronounced for easier aim verification.
  15. On this vehicle you will be verifying the aim of the vertical cutoff on the left side of the lamp vertical bulb centerline as it is projected onto the aim board.
  16. If the location of the cutoff projected onto the board differs, an adjustment to the beam pattern location is necessary.
  17. Adjust the vertical headlamp adjustment screw until the Left Gradient Line (Cutoff Line) is set -2.0 inches below the Horizontal Axis within +/- 2.0 inches (2) measured at 25 feet.
  18. Verify proper aim location.
  19. Repeat the aiming procedure for the passengers side headlamp while blocking the light from projecting onto the screen from the drivers side headlamp.

Scheme 47

Scheme 47: Headlamp Control Module Replacement (Escalade PLATINUM)
Scheme 47: Headlamp Control Module Replacement (Escalade PLATINUM)
CalloutComponent Name
Preliminary Procedure: Remove the headlamp assembly. Refer to Headlamp Replacement (Escalade PLATINUM) .
1ELC Module Screw (Qty: 4) CAUTION: Refer to Fastener Caution . Tighten: Hand tighten the screws evenly after installation of the ELC module to the headlamp connector.
2ELC Module Tip: Pull the module straight from the headlamp connector.
CAUTION
Refer to Fastener Caution .

Scheme 48

Scheme 48: Front Fog Lamp Replacement (Tahoe, Avalanche)
Scheme 48: Front Fog Lamp Replacement (Tahoe, Avalanche)
CalloutComponent Name
Preliminary Procedures Remove either the LF or RF wheelhouse liner. Refer to Front Wheelhouse Liner Replacement - Left Side or Front Wheelhouse Liner Replacement - Right Side . Disconnect the electrical bulb socket from the lamp. From the inside of the front bumper fascia, using a blunt instrument, push outward on the 2 upper mounting studs for the fog lamp. Using the same blunt instrument, push outward on the lower adjustment screw for the fog lamp.
1Forward Lamp Harness Electrical Connector Tip: Disconnect the electrical bulb socket from the lamp.
2Fog Lamp Assembly Tip: Aim the fog lamps after the installation of the fog lamps. Refer to Fog Lamp Aiming (Tahoe/Yukon) .
3Fog Lamp Upper Retainer (Qty: 2) Tip: Secure the retainer into the front bumper fascia prior to re-installing the fog lamp assembly.
4Fog Lamp Adjuster Retainer Tip: Ensure the lower vertical tab on the retainer aligns with the slot in the front bumper fascia.

Scheme 49

Scheme 49: Front Fog Lamp Replacement (Yukon)
Scheme 49: Front Fog Lamp Replacement (Yukon)
CalloutComponent Name
Preliminary Procedures Remove either the LF or RF wheelhouse liner. Refer to Front Wheelhouse Liner Replacement - Left Side or Front Wheelhouse Liner Replacement - Right Side . From the inside of the front bumper fascia, using a blunt instrument, pinch the retainers and push outward on the 2 upper mounting studs for the fog lamp. Using the same blunt instrument, pinch the retainer and push outward on the lower adjustment screw for the fog lamp.
1Forward Lamp Harness Electrical Connector Tip: Disconnect the electrical connector from the fog lamp bulb socket.
2Fog Lamp Upper Retention Studs (Qty: 2) Tip: Ensure the retainers are repositioned into the front bumper fascia mounting holes prior to the installation of the new fog lamp if they become dislodged during the removal of the lamp.
3Fog Lamp Adjuster Screw Tip: Adjust/aim the front fog lamps after the new fog lamps have been installed. Refer to Fog Lamp Aiming (Tahoe/Yukon) .
4Fog Lamp Assembly Tip: Remove the bulb socket from the lamp assembly and transfer as necessary.

Scheme 50

Scheme 50: Front Fog Lamp Replacement (PLATINUM)
Scheme 50: Front Fog Lamp Replacement (PLATINUM)
CalloutComponent Name
Preliminary Procedures Remove the front lower bumper filler. Refer to Front Bumper Filler Replacement (All Utility, Avalanche, Cadillac EXT) or Front Bumper Filler Replacement (Z71) . Disconnect the electrical connectors for the front park turn signal lamp and the front fog lamp sockets. The bulbs can be removed after the lamp housing has been removed from the front bumper fascia.
1Nut (Qty: 3) CAUTION: Refer to Fastener Caution . Tighten: 10 N.m (89 lb in)
2Front Fog Lamp Assembly Tip: Remove the lamp assembly from the front side of the lower bumper fascia.
3Fog Lamp Bulb WARNING: Refer to Halogen Bulb Warning . Tip: Rotate the bulb socket counterclockwise in order to remove.
4Park, Turn Signal Lamp Bulb Socket Tip: Rotate the bulb socket counterclockwise in order to remove.
5Park, Turn Signal Lamp Bulb Tip: Pull the bulb straight from the socket.
CAUTION
Refer to Fastener Caution .
WARNING
Refer to Halogen Bulb Warning .

Scheme 51

Scheme 51: Front Fog Lamp Bulb Replacement (Yukon)
Scheme 51: Front Fog Lamp Bulb Replacement (Yukon)
CalloutComponent Name
1Fog Lamp Connector Tip: Twist the bulb socket counterclockwise and remove the fog lamp bulb.

Scheme 52

Scheme 52: Front Fog Lamp Bulb Replacement (Tahoe)
Scheme 52: Front Fog Lamp Bulb Replacement (Tahoe)
CalloutComponent Name
Preliminary Procedure: Reach under the front bumper fascia in order to access the fog lamp connector and bulb.
1Forward Lamp Harness Electrical Connector
2WARNING: Refer to Halogen Bulb Warning . Fog Lamp Bulb Tip: Rotate the bulb socket counterclockwise in order to remove the bulb socket from the fog lamp housing.
WARNING
Refer to Halogen Bulb Warning .

Scheme 53

Scheme 53: Front Fog Lamp Bulb Replacement (Escalade)
Scheme 53: Front Fog Lamp Bulb Replacement (Escalade)
CalloutComponent Name
Preliminary Procedure: Disconnect the electrical connector for the front fog lamp.
1Forward Lamp Harness Electrical Connector
2WARNING: Refer to Halogen Bulb Warning . Fog Lamp Bulb Tip: Rotate the bulb socket counterclockwise in order to remove the bulb socket from the fog lamp housing.
WARNING
Refer to Halogen Bulb Warning .

Scheme 54

Scheme 54: Rear Fog Lamp Replacement (Cadillac Export)
Scheme 54: Rear Fog Lamp Replacement (Cadillac Export)
CalloutComponent Name
Preliminary Procedure: Open the liftgate in order to access the left tail lamp assembly screws.
1Tail Lamp Assembly Screw (Qty: 2) CAUTION: Refer to Fastener Caution . Tighten: 2 N.m (18 lb in)
2Tail Lamp Assembly Locator Pin (Qty: 2) Tip: Upon tail lamp removal, some effort is needed to disengage the locating pins from the rear body panel retainer nuts.
3Tail Lamp Retainer Nut (Qty: 2)
4Tail Lamp Wiring Harness Assembly Connector
5Tail Lamp Assembly Tip: The bottom bulb in the left tail lamp is the rear fog lamp bulb and will have a red lens. This is an export only item. Upon installation, push inward on the tail lamp in order to seat the 2 locating pins.
CAUTION
Refer to Fastener Caution .

Scheme 55

Scheme 55: Rear Fog Lamp Bulb Replacement (Cadillac Export)
Scheme 55: Rear Fog Lamp Bulb Replacement (Cadillac Export)
CalloutComponent Name
Preliminary Procedure: Remove the left rear tail lamp. Refer to Tail Lamp Replacement (Cadillac) .
1Rear Fog Lamp Bulb

Scheme 56

Scheme 56: Front Fog Lamp Cover Replacement
Scheme 56: Front Fog Lamp Cover Replacement
CalloutComponent Name
1Front Fog Lamp Cover Tip: Release the three tabs from the bumper fascia and push the cover outward to remove.

Fog Lamp Aiming (Tahoe/Yukon)

The front fog lamps must be aimed for proper illumination of the road. The front fog lamp aim should be checked when a new front fog lamp assembly is installed, or if service or repairs in the front end area may have disturbed the front fog lamp mounting.

Preparation Procedure

IMPORTANTHorizontal aim is not adjustable on this vehicle. Vertical aim is adjusted by an adjusting screw located on the bottom rear of the fog lamp. Prior to aiming the fog lamps, perform the following steps
  1. Completely assemble all of the components on the vehicle.
  2. Park the vehicle on a level surface.
  3. Stop all unnecessary operations or work on the vehicle that affect the vehicle trim.
  4. Close the doors and ensure that the vehicle has no load other than the driver.
  5. Stabilize the suspension by rocking the vehicle sideways.
  6. Ensure that the fuel level is 1/2 full.
  7. Ensure that the tires are inflated to the proper pressure.
  8. Ensure that the driver or a similar weight, approximately 75 kg (165 lb), is in the vehicle driver seat.

Aiming Procedure

  1. Park the vehicle on a level surface 7.6 m (25 ft) (3) away from a wall or other flat surface.
  2. Measure the distance from the floor to the center of the fog lamp (5).
  3. Using this measurement, mark the horizontal centerline of the fog lamp (1) on the flat surface directly in front of the vehicle.
  4. Remove the front portion of the front wheel liner in order to access the adjusting screw.
  5. Turn ON the fog lamps.
  6. Reach inside of the front portion of the fender liner in order to access the fog lamp vertical adjustment screw on the bottom of the fog lamp.
  7. Adjust the fog lamp so that the top edge of the fog lamp beam pattern is 100 mm (4 in) below the horizontal centerline (2).
  8. Turn OFF the fog lamps.
  9. Secure the forward edge of the front fender liner.

Scheme 57

Scheme 57: Daytime Running Lamp Bulb Replacement (GMC)
Scheme 57: Daytime Running Lamp Bulb Replacement (GMC)
CalloutComponent Name
Preliminary Procedure: Remove the headlamp assembly. Refer to Headlamp Replacement (GMC Yukon Two-mode Hybrid) or Headlamp Replacement (Yukon) or Headlamp Replacement (Non HID) .
1Daytime Running Lamp Connector
2Daytime Running Lamp Bulb

Scheme 58

Scheme 58: Daytime Running Lamp Bulb Replacement (Cadillac)
Scheme 58: Daytime Running Lamp Bulb Replacement (Cadillac)
CalloutComponent Name
Preliminary Procedure: Remove the headlamp. Refer to Headlamp Replacement (Cadillac Escalade) or Headlamp Replacement (Escalade PLATINUM) or Headlamp Replacement (Non HID) .
1Daytime Running Lamp Bulb Access Cover
2Daytime Running Lamp Bulb

Scheme 59

Scheme 59: Repeater Lamp Replacement (Escalade)
Scheme 59: Repeater Lamp Replacement (Escalade)
CalloutComponent Name
Preliminary Procedure: Remove the front wheelhouse assembly. Refer to Front Wheelhouse Liner Replacement - Left Side or Front Wheelhouse Liner Replacement - Right Side .
1Repeater Lamp Connector
2Repeater Lamp Tabs (Qty: 2) Tip: Release the tabs securing the repeater to the fender.
3Repeater Lamp Assembly

Scheme 60

Scheme 60: Front Side Marker Lamp Replacement (Yukon)
Scheme 60: Front Side Marker Lamp Replacement (Yukon)
CalloutComponent Name
Preliminary Procedure: Remove the headlamp. Refer to Headlamp Replacement (GMC Yukon Two-mode Hybrid) or Headlamp Replacement (Yukon) .
1Front Side Marker Bulb Connector
2Front Side Marker Bulb

Scheme 61

Scheme 61: Front Side Marker Lamp Replacement (Tahoe, Avalanche)
Scheme 61: Front Side Marker Lamp Replacement (Tahoe, Avalanche)
CalloutComponent Name
Preliminary Procedure: Remove the headlamp assembly. Refer to Headlamp Replacement (Chevrolet Tahoe Two-mode Hybrid) or Headlamp Replacement (Tahoe, Avalanche) .
1Front Side Marker Bulb Socket
2Front Side Marker Bulb

Scheme 62

Scheme 62: Parking and Turn Signal Lamp Replacement (Tahoe, Avalanche)
Scheme 62: Parking and Turn Signal Lamp Replacement (Tahoe, Avalanche)
CalloutComponent Name
Preliminary Procedure: Remove the headlamp. Refer to Headlamp Replacement (Chevrolet Tahoe Two-mode Hybrid) or Headlamp Replacement (Tahoe, Avalanche) .
1Park Turn Bulb

Scheme 63

Scheme 63: Parking and Turn Signal Lamp Replacement (Yukon)
Scheme 63: Parking and Turn Signal Lamp Replacement (Yukon)
CalloutComponent Name
Preliminary Procedure: Remove the headlamp. Refer to Headlamp Replacement (GMC Yukon Two-mode Hybrid) or Headlamp Replacement (Yukon) .
1Park Turn Bulb Connector
2Park Turn Bulb

Parking and Turn Signal Lamp Bulb Replacement (Yukon)

CalloutComponent Name
Preliminary Procedure: Remove the headlamp. Refer to Headlamp Replacement (GMC Yukon Two-mode Hybrid) or Headlamp Replacement (Yukon) .
1Park Turn Bulb Connector
2Park Turn Bulb

Scheme 64

Scheme 64: Parking and Turn Signal Lamp Bulb Replacement (Escalade)
Scheme 64: Parking and Turn Signal Lamp Bulb Replacement (Escalade)
CalloutComponent Name
Preliminary Procedures Remove the front lower bumper filler from the side the bulb is being serviced from. Refer to Front Bumper Filler Replacement (All Utility, Avalanche, Cadillac EXT) or Front Bumper Filler Replacement (Z71) . Rotate the bulb socket counterclockwise in order to remove.
1Front Park, Turn Signal Lamp Socket
2Front Park, Turn Signal Lamp Bulb Tip: Pull the bulb straight from the socket.

Scheme 65

Scheme 65: Parking and Turn Signal Lamp Bulb Replacement (Cadillac)
Scheme 65: Parking and Turn Signal Lamp Bulb Replacement (Cadillac)
CalloutComponent Name
Preliminary Procedure: Remove the headlamp. Refer to Headlamp Replacement (Cadillac Escalade) or Headlamp Replacement (Escalade PLATINUM) or Headlamp Replacement (Non HID) .
1Park Lamp Bulb Connector
2Park Lamp Bulb

Parking and Turn Signal Lamp Bulb Replacement (Tahoe, Avalanche)

CalloutComponent Name
Preliminary Procedure: Remove the headlamp. Refer to Headlamp Replacement (Chevrolet Tahoe Two-mode Hybrid) or Headlamp Replacement (Tahoe, Avalanche) .
1Park Turn Bulb

Scheme 66

Scheme 66: High Mount Stop Lamp Replacement (Yukon Two-mode Hybrid)
Scheme 66: High Mount Stop Lamp Replacement (Yukon Two-mode Hybrid)
CalloutComponent Name
Preliminary Procedure: Remove the liftgate upper applique. Refer to Liftgate Upper Applique Replacement (GMC Yukon Two-mode Hybrid) .
1High Mount Stop Lamp Assembly Nut (Qty: 2) CAUTION: Refer to Fastener Caution . Tighten: 9 N.m (80 lb in)
2High Mount Stop Lamp Assembly Tip: Ensure the high mount stop lamp electrical harness is routed and secured to the back body opening upper applique tabs as removed.
3High Mounted Stop Lamp Assembly Tip: There are no serviceable bulbs in the lamp which uses the (LED) light emitting diode for lumination.
CAUTION
Refer to Fastener Caution .

Scheme 67

Scheme 67: High Mount Stop Lamp Replacement (Yukon)
Scheme 67: High Mount Stop Lamp Replacement (Yukon)
CalloutComponent Name
Preliminary Procedure: Remove the high mount stop lamp applique. Refer to Back Body Opening Upper Applique Replacement .
1High Mount Stop Lamp Assembly Nut (Qty: 2) CAUTION: Refer to Fastener Caution . Tighten: 2 N.m (18 lb in)
2High Mount Stop Lamp Assembly
CAUTION
Refer to Fastener Caution .

Scheme 68

Scheme 68: High Mount Stop Lamp Replacement (Avalanche)
Scheme 68: High Mount Stop Lamp Replacement (Avalanche)
CalloutComponent Name
Preliminary Procedure: Remove the center cargo bridge panel. Refer to Cargo Box Bridge Cross Bar Replacement (Avalanche) or Cargo Box Bridge Cross Bar Replacement (Escalade EXT) .
1High Mounted Stop Lamp Attachment Clip (Qty: 2)
2High Mount Stop Lamp Assembly Screw CAUTION: Refer to Fastener Caution . Tighten: 2 N.m (18 lb in)
3High Mount Stop Lamp Assembly
CAUTION
Refer to Fastener Caution .

Scheme 69

Scheme 69: High Mount Stop Lamp Replacement (Escalade)
Scheme 69: High Mount Stop Lamp Replacement (Escalade)
CalloutComponent Name
Preliminary Procedure: Remove the high mount stop lamp applique. Refer to Back Body Opening Upper Applique Replacement .
1CHMSL Electrical Connector
2High Mount Stop Lamp Assembly Nut (Qty: 4) CAUTION: Refer to Fastener Caution . Tighten: 2 N.m (18 lb in)
3High Mount Stop Lamp Assembly
CAUTION
Refer to Fastener Caution .

Scheme 70

Scheme 70: Rear License Plate Lamp Replacement (GMC Denali)
Scheme 70: Rear License Plate Lamp Replacement (GMC Denali)
CalloutComponent Name
1Rear License Plate Lamp Cover Tip: Remove the cover from the bumper assembly using a flat-bladed tool.
2Rear License Plate Lamp Bulb Tip: Pull the bulb straight from the socket in order to replace.

Scheme 71

Scheme 71: Rear License Plate Lamp Replacement (Escalade)
Scheme 71: Rear License Plate Lamp Replacement (Escalade)
CalloutComponent Name
1License Plate Lamp Screw (Qty: 2 each lamp) CAUTION: Refer to Fastener Caution . Tighten: 2 N.m (18 lb in)
2License Plate Lamp Bulb Lens
3License Plate Lamp Bulb
CAUTION
Refer to Fastener Caution .

Scheme 72

Scheme 72: Rear License Plate Lamp Replacement (Yukon Two-mode Hybrid)
Scheme 72: Rear License Plate Lamp Replacement (Yukon Two-mode Hybrid)
CalloutComponent Name
1License Plate Lamp Screw (Qty: 4) CAUTION: Refer to Fastener Caution . Tighten: 2 N.m (18 lb in)
2License Plate Lamp Bulb Lens
3License Plate Lamp Bulb
CAUTION
Refer to Fastener Caution .

Scheme 73

Scheme 73: Tail Lamp Replacement (Avalanche)
Scheme 73: Tail Lamp Replacement (Avalanche)
CalloutComponent Name
Preliminary Procedure: Open the endgate in order to access the tail lamp assembly screws.
1Tail Lamp Assembly Screw (Qty: 2) CAUTION: Refer to Fastener Caution . Tighten: 2 N.m (18 lb in)
2Tail Lamp Wiring Harness Assembly Connector
3Tail Lamp Assembly Tip: Upon installation, push inward on the tail lamp in order to seat the 2 locating pins in the body panel.
CAUTION
Refer to Fastener Caution .

Scheme 74

Scheme 74: Tail Lamp Replacement (GMC Yukon Two-Mode Hybrid)
Scheme 74: Tail Lamp Replacement (GMC Yukon Two-Mode Hybrid)
CalloutComponent Name
Preliminary Procedure: Open the liftgate in order to access the tail lamp assembly screws.
1Tail Lamp Assembly Screw (Qty: 2) CAUTION: Refer to Fastener Caution . Tighten: 2.5 N.m (22 lb in)
2Tail Lamp Electrical Harness Assembly Connector Tip: Disconnect the tail lamp bulb and side marker lamp bulb sockets from the lamp assembly.
3Tail Lamp Assembly Tip: Upon installation, push inward on the outer edge of the tail lamp in order to seat the 2 locating pins to the outer body panel nuts.
CAUTION
Refer to Fastener Caution .

Tail Lamp Replacement (Chevrolet Tahoe Two-Mode Hybrid)

CalloutComponent Name
Preliminary Procedure: Open the liftgate in order to access the light emitting diode (LED) tail lamp assembly screws.
1Tail Lamp Assembly Screw (Qty: 2) CAUTION: Refer to Fastener Caution . Tighten: 2.5 N.m (22 lb in)
2Tail Lamp Electrical Harness Assembly Connector Tip: Disconnect the tail lamp electrical connector from the rear tail lamp assembly.
3Tail Lamp Assembly Tip: Upon installation, push inward on the outer edge of the tail lamp in order to seat the 2 locating pins to the outer body panel nuts prior to installing the screws.
CAUTION
Refer to Fastener Caution .

Tail Lamp Replacement (Cadillac)

CalloutComponent Name
Preliminary Procedure: Open the liftgate in order to access the tail lamp assembly screws.
1Tail Lamp Assembly Screw (Qty: 2) CAUTION: Refer to Fastener Caution . Tighten: 2 N.m (18 lb in)
2Tail Lamp Assembly Locator Pin (Qty: 2) Tip: Upon tail lamp removal, some effort is needed to disengage the locating pins from the rear body panel retainer nuts.
3Tail Lamp Retainer (Qty: 2)
4Tail Lamp Wiring Harness Assembly Connector
5Tail Lamp Assembly Tip: Upon installation of the tail lamp, push inward on the lamp in order to seat the 2 locator pins into the retainer nuts.
CAUTION
Refer to Fastener Caution .

Scheme 75

Scheme 75: Tail Lamp Replacement (Tahoe, Yukon)
Scheme 75: Tail Lamp Replacement (Tahoe, Yukon)
CalloutComponent Name
Preliminary Procedure: Open the liftgate in order to access the tail lamp assembly screws.
1Tail Lamp Assembly Screw (Qty: 2) CAUTION: Refer to Fastener Caution . Tighten: 2 N.m (18 lb in)
2Tail Lamp Assembly Locator Pin (Qty: 2) Tip: Upon tail lamp removal, some effort is needed to disengage the locating pins from the rear body panel retainer nuts.
3Tail Lamp Retainer Nut (Qty: 2)
4Tail Lamp Wiring Harness Assembly Connector
5Tail Lamp Assembly Tip: Upon installation, push inward on the tail lamp in order to seat the 2 locating pins.
CAUTION
Refer to Fastener Caution .

Scheme 76

Scheme 76: Tail Lamp Bulb Replacement (Yukon)
Scheme 76: Tail Lamp Bulb Replacement (Yukon)
CalloutComponent Name
Preliminary Procedure: Remove the rear tail lamp. Refer to Tail Lamp Replacement (GMC Yukon Two-Mode Hybrid) or Tail Lamp Replacement (Tahoe, Yukon) .
1Back Up Lamp Bulb
2Park Turn Bulb (Qty: 2)
3Side Marker Bulb

Tail Lamp Bulb Replacement (Cadillac)

CalloutComponent Name
Preliminary Procedure: Remove the rear tail lamp. Refer to Tail Lamp Replacement (Cadillac) .
1Back Up Lamp Bulb Tip: Rotate the bulb socket and remove the bulb.

Scheme 77

Scheme 77: Tail Lamp Bulb Replacement (Tahoe, Avalanche)
Scheme 77: Tail Lamp Bulb Replacement (Tahoe, Avalanche)
CalloutComponent Name
Preliminary Procedure: Remove the rear tail lamp. Refer to Tail Lamp Replacement (Avalanche) or Tail Lamp Replacement (Chevrolet Tahoe Two-Mode Hybrid) or Tail Lamp Replacement (Tahoe, Yukon) .
1Back Up Lamp Bulb
2Park Turn Bulb (Qty: 2)
3Side Marker Bulb

Scheme 78

Scheme 78: Tail Lamp Bulb Replacement (Tahoe)
Scheme 78: Tail Lamp Bulb Replacement (Tahoe)
CalloutComponent Name
Preliminary Procedure: Remove the rear tail lamp. Refer Tail Lamp Replacement (Chevrolet Tahoe Two-Mode Hybrid) or Tail Lamp Replacement (Tahoe, Yukon) .
1Back Up Lamp Bulb Tip: Rotate the lamp socket counter-clockwise and remove from the lamp assembly.
2Park Turn Directional Bulb
3Side Marker Lamp Bulb Tip: Rotate the bulb socket and pull the marker lamp bulb from the socket.
4Park Turn Directional (LED) Tip: The upper portion of the lamp assembly is not serviceable.

Scheme 79

Scheme 79: Tail Lamp Bulb Replacement (Yukon Two-mode Hybrid)
Scheme 79: Tail Lamp Bulb Replacement (Yukon Two-mode Hybrid)
CalloutComponent Name
Preliminary Procedure: Remove the rear tail lamp. Refer to Tail Lamp Replacement (GMC Yukon Two-Mode Hybrid) .
1Back Up Lamp Bulb WARNING: Refer to Halogen Bulb Warning . Procedure Twist the bulb socket counter-clockwise and remove the bulb socket from the lamp housing. Pull the lamp bulb straight from the bulb socket.
2Turn Signal Bulb Tip: The top of the rear lamp is (LED) Light Emitting Diode which is not serviceable.
3Side Marker Bulb Tip: Twist the bulb socket and remove the side marker lamp bulb.
WARNING
Refer to Halogen Bulb Warning .

Exterior Lamps

The exterior lighting system consists of the following lamps

  1. The headlamps
  2. The daytime running lamps (DRL)
  3. The front fog lamps
  4. The rear fog lamp (export only)
  5. The park, tail and marker lamps
  6. The exterior courtesy lamps
  7. The turn signal/hazard lamps
  8. The side repeater lamps (export only)
  9. The stop lamps
  10. The backup lamps
  11. The cargo lamps
  12. The clearance lamps

Headlamps

The headlamps may be turned ON in 2 different ways. First, when the driver places the headlamp switch in the HEADLAMP position, for normal operation. Second, with the headlamp switch placed in the AUTO position, for automatic lamp control (ALC). During ALC the headlamps will be in DRL operation in daylight conditions, or headlamp operation in low light conditions.

Headlamp ON/OFF control is determined by the body control module (BCM) by a signal on the headlamp switch on input circuit when the headlamp switch is in the HEAD position. When the headlamp switch is in the AUTO position, the BCM determines headlamps ON/OFF by the voltage from the ambient light sensor.

If the headlight switch is left in the ON position, the inadvertent power control feature will turn OFF the headlights approximately 10 minutes after the ignition switch is turned to the OFF position. If the driver places the headlight switch in the ON position after the ignition switch has been turned OFF, or if the ignition switch is in the ACCY position, the headlights will remain ON until turned OFF or the battery runs dead.

The high beam indicator is illuminated when the instrument cluster receives a serial data message from the BCM that the high beams are illuminated.

High Beams

The high beam headlamps receive voltage from the headlamp high relay located in the underhood fuse block. The BCM controls the relay on the headlamp high beam relay control circuit. High beam control is determined by a signal on the headlamp dimmer switch signal circuit from the multifunction switch. When the headlamp dimmer switch signal circuit is grounded, the BCM grounds the headlamp high beam relay control circuit, illuminating the high beam headlamps. The right and left high beam circuits are independent and are fused independently in the underhood fuse block.

Low Beams - Standard

The low beam headlamps receive voltage from the headlamp low beam relay located in the underhood fuse block. The BCM controls the relay on the headlamp low beam relay control circuit. Low beam control is determined by a signal on the headlamp dimmer switch signal circuit from the multifunction switch. When the headlamp dimmer switch signal circuit is open, the BCM grounds the headlamp low beam relay control circuit, illuminating the low beam headlamps. The right and left low beam circuits are independent are fused independently in the underhood fuse block.

Low Beams - High Intensity Discharge (HID)

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

Normal operation of the HID system starts at the ballast. The headlamp ballast input connector receives battery positive voltage from fuses in the underhood fuse block. When the low beam headlamps are requested the low beam relay supplies voltage to the ballast on the right headlamp low beam supply voltage circuit and the left headlamp low beam supply voltage circuit, which in turn begins the low beam operation as follows. As soon as the input power is applied, the ballast draws 20 amps from the battery for 5-10 seconds, depending on the input voltage level. The ballast is then able to charge the 2 outputs leading to the start to -360 volts and +800 volts. Negative 360 volts and +800 volts are the voltages needed by the starter to strike or start the lamp. HID headlamps do not have filaments like traditional bulbs, instead, the starter uses a high voltage transformer to convert the +800 volts input power into 25,000 volts. The increased voltage is used in order to create an arc between the electrodes in the bulb. The creation of this arc begins the start up process.

Low Voltage Operation of HID Headlamps

The BCM monitors the vehicle system voltage while in the RUN power mode. When the system voltage drops below 8.9 volts, the following will occur

  1. STAGE 1: If the low beam headlamps are ON, either manually or automatically, the BCM will turn ON the high beam headlamps by activating the High Beam output.
  2. STAGE 2: When the system voltage drops below 8.5 volts, the following will occur: If the low beam headlamps are currently ON, either manually or automatically, the BCM will turn OFF the low beam headlamps by deactivating the Low Beam output. If the headlamps are then turned ON manually, the manual switch redundancy will cause the low beam headlamps to remain ON.

If during the same ignition cycle, the BCM enters either STAGE 1 or STAGE 2 operations noted above, and then determines that the system voltage has risen, the following will occur

  1. If the BCM has entered STAGE 2 operation, it will not return to STAGE 1 operation until the system voltage rises above 9.4 volts.
  2. If the BCM has entered STAGE 1 operation, it will not return to normal operation until the system voltage rises above 9.8 volts.

Electrical System Requirements with HID

Ensure that the battery and the harness are capable of supplying up to 20 amps of current per ballast, with less than 2 volts of system loss or voltage drop. Each ballast requires the 20 amps in order to ensure normal startup and run up of the lamp. Run up is the term used to describe the extra power level given to the bulb from the -360-volt ballast output. The input current during the steady state operation is 3.4 amps at 12.8 volts.

Run Up of the HID Lamp

After the lamp receives the strike from the starter and the arc is established, the ballast uses its -360-volt output in order to provide the run up power needed in order to keep the lamp ON. The lamp rapidly increases in intensity from a dim glow to a very high-intensity, bright light called a steady state. Within 2 seconds of the arc being established in the bulb, 70 percent of steady state is complete. 100 percent of the steady state is completed within 30 seconds. A 75-watt power level is necessary in order to bring the lamp to a steady state in the required period of time.

When to Change the HID Bulb

Bulb failure occurs when the bulb gets older and becomes unstable. The bulb may begin shutting itself OFF sporadically and unpredictably at first, perhaps only once during a 24 hour period. When the bulb begins shutting itself OFF occasionally, the ballast will automatically turn the bulb back ON again within 0.5 second. The ballast will re-strike the bulb so quickly that the bulb may not appear to have shut OFF. As the bulb ages, the bulb may begin to shut OFF more frequently, eventually over 30 times per minute. When the bulb begins to shut OFF more frequently, the ballast receives excessive, repetitive current input (20 amps). Repetitive and excessive restarts or re-strikes, without time for the ballast to cool down, will permanently damage the ballast. As a safeguard, when repetitive re-strikes are detected, the ballast will not attempt to re-strike the lamp. The ballast then shuts down and the bulb goes out.

The following symptoms are the noticeable signs of bulb failure

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

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

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

Light Color (w/HID)

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

Daytime Running Lamps (DRL)

The DRL will only operate while the engine is running, is in gear, and the headlamp switch is in the AUTO position. When these conditions have been met and the ambient light sensor indicates daytime conditions, the DRL will illuminate. The ambient light sensor is a light sensitive transistor that varies its voltage signal to the BCM in response to changes to the outside ambient light level. When the BCM receives this signal it will either turn ON the dedicated DRL on the X88/Z75, the low beam headlamps only as DRL on the Z88, or the headlamps, park, and tail lamps for auto headlamp operation in low light conditions. Any function or condition that turns ON the headlights will cancel the DRL operation. The DRL can be manually turned OFF by activating the AHL/DRL switch in the headlamp switch. The AHL/DRL defeat switch sends a ground signal through the DRL switch signal circuit to the BCM. The BCM then turns OFF the DRL. When the AHL/DRL are manually turned OFF at the headlamp switch, the AHL/DRL will default to ON with the next ignition cycle. With the headlight switch in the AUTO position, the DRL will either be turned ON or OFF after an approximate 8 second delay, depending on whether daylight or low light conditions are sensed. When the BCM energizes the DRL relay, the DRL receives voltage on the DRL supply voltage circuit.

IntelliBeam Intelligent High-Beam Headlamp Control System

IntelliBeam is an enhancement to your vehicles headlamp system. Using a digital light sensor on the rearview mirror, the system will turn the vehicles high beam headlamps ON and OFF according to surrounding traffic conditions. The IntelliBeam system will turn ON the high-beam headlamps when it is dark enough, there is no other traffic present, and the IntelliBeam system is enabled. When the conditions are met, the inside rearview mirror will send a serial data message to the BCM requesting high beam headlamp operation.

Activating and Enabling IntelliBeam

Press and release the IntelliBeam button on the inside rearview mirror. The IntelliBeam indicator on the mirror will illuminate to indicate the system has been turned ON. Once the systems has been turned ON, it will remain ON each time the vehicle is started. Additionally, the IntelliBeam system must be enabled. To enable the IntelliBeam system, turn the exterior lamp control to AUTO, with the turn signal/multifunction lever in its neutral position. The high beam ON light will appear on the instrument panel cluster when the high beams are ON.

Driving with IntelliBeam

IntelliBeam will only activate the high-beams when driving over 32 km/h (20 mph). The high beam headlamps will remain ON, under the automatic control of IntelliBeam, until any of the following situations occur

  1. The system detects an approaching vehicles headlamps.
  2. The system detects a preceding vehicles tail lamps.
  3. The outside light is bright enough that the high-beam headlamps are not required.
  4. The vehicles speed drops below 24 km/h (15 mph).
  5. The headlamp stalk is moved forward to the high-beam position or the flash-to-pass feature issued. See when either of these conditions occur, the IntelliBeam feature will be disabled and the IntelliBeam light in the mirror will turn OFF until the high-beam stalk is returned to the neutral position.
  6. If IntelliBeam was using low-beams prior to this action, the IntelliBeam feature will be temporarily disabled until the stalk is returned to the neutral position.
  7. The exterior lamp control is turned to any setting except AUTO. When this occurs, IntelliBeam will be disabled until the control is turned back to the AUTO position.
  8. The IntelliBeam system is turned OFF at the inside rearview mirror.

The high beam headlamps may need to manually disabled or canceled by turning the low beam headlamps ON, if any of the above conditions exist.

Disabling and Resetting IntelliBeam at the Rearview Mirror

IntelliBeam can be disabled by using the controls on the inside rearview mirror.

AUTO (On/Off)

To disable the system, press this button on the inside rearview mirror. The IntelliBeam indicator will turn OFF and then will not come back ON until the IntelliBeam button is pressed again.

Stalk Disable

When IntelliBeam has turned ON the high-beams, pull or push the high-beam stalk. This will disable IntelliBeam. The IntelliBeam indicator on the mirror will turn OFF. To re-enable IntelliBeam, press the IntelliBeam button on the mirror.

Fog Lamps

With both the ignition switch in the RUN position, and the park lamps ON, the fog lights will illuminate when the driver depresses the fog lamp switch. The BCM receives the park lamp ON signal from the interior park lamps supply voltage signal circuit. With the headlamp switch in either the park or headlamp position, and the fog lamp switch is in the ON position, the BCM will ground the fog lamp relay control circuit causing the relay to energize. The current flows from the fog lamp relay to both front fog lamps. The state of the fog lamps will remain the same until the fog lamp switch position is changed, or the ignition switch is cycled OFF and ON. Fog lamp operation will be cancelled whenever the park lamps are turned OFF or the high beam headlights have been selected.

The rear fog lamp will illuminate when the driver presses the rear fog lamp switch. The auxiliary body control module (XBCM) controls and supplies battery positive voltage to both the rear fog lamp and trailer rear fog lamp circuits.

Park, Tail and Marker Lamps

The park, tail and marker lamps, including the license lamps, are turned ON when the headlamp switch is placed in the PARK or HEAD position or anytime the headlights are requested. The underhood fuse block supplies battery positive voltage to both the park lamp relay switch contacts and the park lamp coil circuit. The BCM provides a ground or control circuit to the park lamp relay coil circuit. When the park lamps are turned ON, the BCM energizes the park lamp relay. If the headlight switch is left in the ON position, the inadvertent power control feature will turn OFF the park, tail and marker lamps approximately 10 minutes after the ignition switch is turned to the OFF position. If the driver places the headlight switch in the ON position after the ignition switch has been turned OFF, or if the ignition switch is in the ACCY position, the park, tail and marker lamps will remain ON until turned OFF or the battery runs dead.

Exterior Courtesy Lamps

The BCM, driver door switch, and the passenger door switch communicate via GMLAN serial data. The driver door switch and passenger door switch supply power and ground to the left and right exterior lamps respectively. When the BCM commands illuminated entry, a command is also sent to the door switches for illumination of the exterior courtesy lamps. If the door locks are activated to the LOCK position, or if the ignition switch is turned to either the ON or RUN position the exterior courtesy lamps will deactivate immediately. For additional information concerning illuminated entry, refer to the vehicles owners manual.

Turn Signal/Hazard Lamps

When the turn signal switch is placed in either the left or right position, a ground signal is completed from the turn signal switch to the BCM. When the hazard flasher switch is activated, a ground signal is completed from the turn signal/hazard switch to the BCM. The BCM then sends an ON-OFF voltage signal through the fuses to the appropriate turn signal and side repeater (export only) lamps or to all of the turn signal fuses for hazard operation. The driver door switch and passenger door switch also receive voltage from the BCM turn signal supply voltage circuits for the mirror turn signals. The door switches have no function or control of the mirror turn signals other than a pass through connection for the circuits. The audio chime is also activated when the turn signals are ON. The instrument panel cluster (IPC) receives the signals to activate the turn signal indicators over the GMLAN serial data system. When the hazard switch is pressed, all turn signal lamps will flash including both IPC turn indicators.

On certain export vehicles, the auxiliary body control module (XBCM) controls and supplies voltage for all of the trailer lighting functions.

Stop Lamps

When the driver presses the brake pedal, the switch contacts open and battery positive voltage is interrupted to the BCM. The BCM then supplies voltage to both the turn/stop lamp supply voltage circuit and trailer rear turn/stop lamp supply voltage circuits. The BCM also supplies voltage to the CHMSL though a dedicated circuit.

Backup Lamps

The backup lamp request signal is sent from the PCM to the BCM on the GMLAN serial data system. This signal is based on the park neutral position (PNP) switch signal. The BCM supplies voltage to the backup relay and to the automatic day/night mirror when the vehicle is in reverse. The backup relay supplies a voltage on the backup lamp supply voltage circuit to the backup lamps and trailer backup circuit.

Cargo Lamps

The cargo lamp is controlled by the dome lamp control circuit. There is not a separate switch to turn the cargo lamps ON and OFF.

Clearance Lamps

The clearance lamps, are turned ON when the headlamp switch is placed in the PARK or HEAD position or anytime the headlamps are requested. The underhood fuse block supplies battery positive voltage to both the park lamp relay switch contacts and the park lamp coil circuit. The BCM provides a ground or control circuit to the park lamps relay coil circuit. When the park lamps are turned ON, the BCM energizes the park lamp relay. If the headlamp switch is left in the ON position, the inadvertent power control feature will turn OFF the park, tail and clearance lamps approximately 10 minutes after the ignition switch is turned to the OFF position. If the driver places the headlamp switch in the ON position after the ignition switch has been turned OFF, or if the ignition switch is in the ACCY position, the park, tail and marker lamps will remain ON until turned OFF or the battery runs dead.

Interior Lamps

The interior lighting consists of 2 groups. The first group includes lamps that may not be dimmed.

  1. Courtesy/illuminated entry lamps
  2. Dome lamps
  3. Map lamps
  4. Reading lamps
  5. Vanity mirror lamps

Courtesy/Illuminated Entry Lamps

The courtesy/illuminated entry lamps, may be manually turned ON or OFF by placing the interior lamp switch in the ON or OFF position. If an outside door handle is lifted and a door is opened, the courtesy/illuminated entry lamps illuminate. After all the doors have been closed the courtesy/illuminated entry lamps will remain illuminated approximately 15 seconds. The body control module (BCM) will then turn them OFF through the theater dimming feature. The courtesy/illuminated entry lamps will also turn ON prior to any door being opened, and remain illuminated approximately 40 seconds when the driver removes the ignition key. When the driver places the dome lamp defeat switch in the OFF position, the courtesy/illuminated entry lamps will be disabled.

The BCM, the door switches, and the liftgate module (LGM) (if equipped with power liftgate) communicate through the GMLAN serial data circuit for the lamp illumination commands of the doors, liftgate, and liftglass open/ajar switch signals. The LGM receives a ground signal from the pawl switch, ratchet switch, and liftglass ajar switch that are located within the liftgate latch and liftglass latch. For all vehicles, the left and right rear door latch switches are both on one circuit that is also an input to the BCM.

If the vehicle has a manual liftgate, there is an input circuit from the liftgate latch switch and liftglass latch switch directly to the BCM.

The left and right front door courtesy lamps receive voltage and ground from the driver door switch and the passenger door switch respectively. The remaining courtesy lamps are controlled and receive voltage through the BCM from the CTSY fuse in the instrument panel fuse block.

Door Sill Illumination

The door sill lighting is a dealer installed accessory. When the body control module (BCM) receives a signal to command the courtesy lamps ON, it applies battery voltage through the dome/courtesy lamps control circuit to the courtesy lamps. The door sill illumination receives voltage through the courtesy lamps circuit. The door sill illumination harness connector includes a power inverter which converts the battery voltage to 150 V AC (550 Hz). This AC voltage is supplied to the door sill lamps and causes them to illuminate.

Keyless Entry Interior Illumination

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

When the driver uses the remote function actuator transmitter to unlock the doors, trunk or presses the panic button, the BCM will keep the courtesy lamps ON approximately 40 seconds. When the driver uses the remote function actuator transmitter to lock the doors, the BCM will keep the courtesy lamps on approximately 2 seconds. If the ignition switch is turned to either the RUN or CRANK position the courtesy lamps will turn OFF immediately.

Vanity Lamps

The inadvertent power supply voltage circuit of the body control module (BCM) provides battery positive voltage to each vanity mirror lamp. When the vanity mirror cover on the sunshade is opened, a switch closes to provide a ground circuit and the vanity lamp illuminates.

Reading Lamps

The inadvertent power supply voltage circuit of the body control module (BCM) provides battery positive voltage to the reading lamps. The reading lamps and switch are integral to the courtesy/reading lamp assembly. When the switch is closed, voltage is supplied and the lamp illuminates.

Battery Rundown Protection/Inadvertent Power

The body control module (BCM) inadvertent power supply voltage circuit provides battery positive voltage from the IS LAMPS fuse in the instrument panel fuse block to all of the interior reading lamps, visor vanity mirror lamps, and cargo lamps if equipped. In the event that any of these lamps were to remain illuminated for a period of more than 10 minutes with the ignition switch in the OFF position, the BCM will deactivate the inadvertent power supply voltage circuit to prevent a total battery discharge condition.

Interior Lamps Dimming

The second interior lighting group includes lamps which may be dimmed. This group may use a combination of vacuum fluorescent (VF) illumination, LED illumination and incandescent lamps.

When the ignition switch is turned to the RUN position, the radio VF display turns ON at maximum brightness. When the park lamps are ON, all incandescent and LED back lighting turn ON at the dimming level indicated by the instrument panel (I/P) dimmer switch. At the same time all VF displays dim to match the indicated dimming level. The panel dimmer switch potentiometer is an input to the body control module (BCM). When the driver selects a dimming setting by moving the I/P dimming switch potentiometer, all incandescent back lighting lamps are provided with a specific voltage. When the I/P dimmer switch is moved from MIN to MAX, all VF displays, as well as all incandescent back lighting respond from minimum intensity to maximum brightness in response to the I/P dimmer switch.

The left and right front door switch illumination is controlled, receives voltage and ground from the driver door switch and passenger switch respectively. The radio is also a GMLAN module and has full control of its illumination. The BCM, door switches, and radio communicate through GMLAN serial data for the lamp illumination commands.

The interior back lighting and indicators that are supplied through the BCM are controlled through the following control circuits

  1. LED Backlight Dimming Control Circuit from IS LAMPS fuse
  2. Indicator Dimming Control Circuit from IS LAMPS fuse
  3. Instrument Panel Lamp Dimming Control Circuit from DIM fuse

The following indicators receive voltage from the BCM and are controlled by ground from a switch or from various modules

  1. Tow indicator
  2. Transfer case control switch 4WD position indicators
  3. Fog lamp indicators
  4. Radio
  5. Analog clock
  6. HVAC control assembly
  7. Instrument panel cluster (IPC)
  8. Driver information center (DIC)
  9. Headlamp and panel dimmer switch
  10. Rear parking assist (RPA) indicator

The indicators receive voltage from the BCM on the LED dimming circuit. Control for the indicators is from the various modules or switches. Voltage for the LED dimming supply circuit, instrument panel lamps dimming control circuit and the instrument panel lamps dimming supply circuit is from the BCM.

The modules controlling the above indicators are as follows

  1. Transfer case shift control module
  2. Object detection module
  3. Windshield washer solvent heater
  4. BCM

See also:
• Diagnostic System Check - Vehicle
• Strategy Based Diagnosis
• Diagnostic Procedure Instructions
• Component Connector End Views
• Circuit Testing
• Connector Repairs
• Testing for Intermittent Conditions and Poor Connections
• Wiring Repairs
• Control Module References
• Diagnostic Repair Verification
• Relay Replacement (Attached to Wire Harness)
• Checking Aftermarket Accessories
• Door Ajar Indicator Malfunction
• Turn Signal Multifunction Switch Replacement
• Front Seat Heater Switch Replacement
• Steering Wheel Control Switch Assembly Replacement
• Driver Information Display Switch Replacement (Except Cadillac)
• Knee Bolster Replacement (Cadillac)
• Fastener Caution
• Fastener Tightening Specifications
• Front Bumper Fascia Replacement (Avalanche)
• Front Wheelhouse Liner Replacement - Left Side
• Front Wheelhouse Liner Replacement - Right Side
• Halogen Bulb Warning
• Liftgate Upper Applique Replacement (GMC Yukon Two-mode Hybrid)
• Cargo Box Bridge Cross Bar Replacement (Avalanche)
• DTC B1395
• Tail Lamp Replacement (Chevrolet Tahoe Two-Mode Hybrid)
• Tail Lamp Replacement (Cadillac)
• Tail Lamp Bulb Replacement (Cadillac)
• Fog Lamp Switch Replacement
• Parking and Turn Signal Lamp Bulb Replacement (Yukon)
• Fastener Tightening Specifications
• Headlamp Aiming (Tahoe/Yukon)
• Headlamp Aiming (Escalade)
• Fog Lamp Aiming (Tahoe/Yukon)