Backup Lamps Malfunction

Backup Lamps Malfunction

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.



Circuit/System Description

The R-BEC 1 fuse in the underhood fuse block supplies battery positive voltage to the BACKUP LAMP relay through the BACKUP LAMP fuse. When the gear selector is placed in reverse, the body control module (BCM) supplies ground to the BACKUP LAMP relay. This energizes the BACKUP LAMP relay and current flows from the BACKUP LAMP relay to the backup lamps and then to ground. The backup lamps are grounded at G401 and G403.


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 Verification

1. Place the gear selector in PARK or Neutral.
2. Ignition ON, observer the backup lamps. The backup lamps should not be illuminated.

• If the backup lamps are illluminated, refer to Backup Lamps Always On

3. Refer to Backup Lamps Inoperative



Circuit/System Testing


Backup Lamps Always On
1. Ignition OFF, disconnect the BU/LP relay.
2. Ignition ON, verify that the backup lamps are not illuminated.

• If the backup lamps are illuminated, test the relay controlled output circuit for a short to voltage.
• If all circuits test normal, replace the BU/LP relay.




Backup Lamps Inoperative
1. Ignition OFF, disconnect the BU/LP relay.
2. Ignition ON, verify that a test lamp illuminates between the relay switch B+ circuit and ground.

• If the test lamp does not illuminate, replace the rear fuse block.

3. Test the relay controlled output circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BU/LP relay.



Repair Instructions

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

* Rear Electrical Center or Junction Block Replacement (Service and Repair)
* Relay Replacement (Attached to Wire Harness) (Relay Replacement (Attached to Wire Harness))Relay Replacement (Within an Electrical Center) (Relay Replacement (Within an Electrical Center))