Backup Lamps Malfunction (Manual Transmission)

Backup Lamps Malfunction (Manual Transmission)

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle (Initial Inspection and Diagnostic Overview) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Initial Inspection and Diagnostic Overview) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Initial Inspection and Diagnostic Overview) provides an overview of each diagnostic category.

Diagnostic Fault Information





Circuit/System Description

Battery voltage is applied from the HTD/SEAT/BCK/UP fuse located in the underhood fuse block to the backup lamp switch when the ignition switch is in the RUN or CRANK positions. When the transmission is placed in the REVERSE position, the backup lamp switch contacts close providing battery voltage to the backup lamps. The backup lamps are permanently grounded at G401 for the left and G402 for the right. With both power and ground the backup lamps illuminate. Once the driver moves the gear selector out of the REVERSE position, the backup lamp switch contacts open and the backup lamps turn OFF.

Reference Information
Schematic Reference

Exterior Lights Schematics (Exterior Lights Schematics)
Connector End View Reference

Component Connector End Views (Connector Views)
Description and Operation

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

* Circuit Testing (Component Tests and General Diagnostics)
* Connector Repairs (Component Tests and General Diagnostics)
* Testing for Intermittent Conditions and Poor Connections (Component Tests and General Diagnostics)
* Wiring Repairs (Component Tests and General Diagnostics)

Scan Tool Reference

Control Module References (Programming and Relearning) for scan tool information

Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the inoperative backup lamp.
2. Ignition OFF, exterior lamps OFF, test for less than 5 ohms between the ground circuit terminal B and ground.

• If greater than the specified range, test the ground circuit for an open/high resistance.

3. Connect the harness connector at the inoperative backup lamp.
4. Ignition OFF, disconnect the harness connector at the backup lamp switch.
5. Ignition ON, verify that a test lamp illuminates between the B+ circuit terminal A and ground.

• If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.

6. Verify that a test lamp does not illuminate between the control circuit terminal B and ground.

• If the test lamp illuminates, test the control circuit for a short to voltage.

7. Connect a 10 A fused jumper between the B+ circuit terminal A and the control circuit terminal B. Ignition ON, verify the backup lamps are illuminated.

• If the backup lamps do not illuminate, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, test or replace the inoperative backup lamp.

8. If all circuits test normal, replace the backup lamp switch.

Repair Instructions

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

* Backup Lamp Replacement (Pontiac G5) (Service and Repair)Backup Lamp Replacement (Chevrolet Coupe) (Service and Repair)
* Backup Lamp Switch Replacement (Service and Repair)