When the PRNDL is placed in the REVERSE position, a signal is sent to the body control module (BCM). The BCM then applies voltage through the backup lamps relay control circuit to the BACK/UP lamp relay in the underhood fuse block, inside rearview mirror, and rearview camera module. The BACK/UP lamp relay then illuminates the backup lamps.

The BCM detects a short to ground on the backup lamp relay control circuit when the backup lamps are being commanded ON.

The backup lamps do not illuminate.

Schematic Reference

Exterior Lights Schematics

Connector End View Reference

Lighting Systems Connector End Views

Electrical Information Reference

Scan Tool Reference

Ignition ON, activate the Backup Lamps output control on the scan tool. The Backup Lamps parameter in the data list should display On and the backup lamps should illuminate.

1. Ignition OFF, disconnect the underhood fuse block connector C 5, inside rearview mirror, and rearview camera module (if equipped) that are in the circuit.
2. Ignition OFF, disconnect the BCM harness connector C2 and test for a ground signal at the connector terminal 22.

⇒	If the circuit exhibits a ground signal, repair the short to ground in the control circuit.

3. Reconnect the inside rearview mirror and test the BCM harness connector  C2, terminal 22 again for ground.

⇒	If the circuit now exhibits a ground signal of 20 ohms or less, replace the inside rearview mirror.

4. Reconnect the underhood fuse block connector and test the BCM harness connector  C2, terminal 22 again for ground.

⇒	If the circuit now exhibits a ground signal of 20 ohms or less, replace the underhood fuse block.

5. If equipped, reconnect the rearview camera module and test the BCM harness connector C2, terminal 22 again for ground.

⇒	If the circuit now exhibits a ground signal of 20 ohms or less, replace the rearview camera module.

⇒	If the circuit does not exhibit a ground, replace the BCM.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.