Backup Lamps Malfunction

Backup Lamps Malfunction

Diagnostic Instructions

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

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 illuminated, 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 after completing the diagnostic procedure. Verification Tests

* Rear Fuseblock Replacement
* Relay Replacement (Attached to Wire Harness)