Operation CHARM: Car repair manuals for everyone.
Home >> Chevrolet >> 2011 >> Tahoe 4WD V8-5.3L >> Repair and Diagnosis >> Lighting and Horns >> Testing and Inspection >> Stop Lamps Malfunction

Stop Lamps Malfunction




Stop Lamps Malfunction

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis Strategy Based Diagnosis for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions Diagnostic Procedure Instructionsprovides an overview of each diagnostic category.

Diagnostic Fault Information






Circuit/System Description

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 12 V 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.

Reference Information
Schematic Reference

Exterior Lights Schematics Exterior Lights Schematics
Connector End View Reference

Component Connector End Views Connector End Views By Name
Description and Operation

Exterior Lighting Systems Description and Operation Exterior Lighting Systems
Electrical Information Reference

* Circuit Testing Circuit Testing
* Connector Repairs Connector Repairs
* Testing for Intermittent Conditions and Poor Connections Testing for Intermittent Conditions and Poor Connections
* Wiring Repairs Wiring Repairs

Scan Tool Reference

Control Module References Programming and Relearningfor scan tool information

Circuit/System Verification

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.

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.

3. Observe the center high mounted stop lamp while pressing and releasing the brake pedal. The center high mounted stop lamp should turn ON and OFF.

• If the center high mounted stop lamp does not change between the selected states, refer to Center High Mounted Stop Lamp Malfunction.

Circuit/System Testing

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 2 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 approximately 1023 counts.

• 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 ohm between the ground circuit terminal of the harness connector listed 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 Mounted 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 ohm 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 mounted stop lamp.

Repair Instructions

Perform the Diagnostic Repair Verification Verification Tests after completing the diagnostic procedure.

* Stop Lamp Switch Replacement
* High Mount Stop Lamp Replacement
* Tail Lamp Bulb Replacement
* Tail Lamp Replacement
* Control Module References Programming and Relearningfor BCM replacement, setup, and programming

pro multis · About Operation CHARM