Circuit/System Testing

Backup Lamp Switch Malfunction

1. Ignition OFF, disconnect the harness connector at the B16 backup lamp switch.
2. Ignition OFF, exterior lamps OFF, doors CLOSED, wait 30 seconds, test for less than 5 Ω between the ground circuit terminal 2 and ground.
   • If greater than the specified range, test the ground circuit for an open/high resistance.
3. Ignition ON, verify the scan tool Reverse Position Switch parameter is OFF.
   • If not the specified value, test the signal circuit terminal 1 for a short to ground. If the circuit tests normal, replace the K20 engine control module.
4. Install a 3 A fused jumper wire between the signal circuit terminal 1 and the ground circuit terminal 2. Verify the scan tool Reverse Position Switch parameter is ON.
   • If not the specified value, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the K20 engine control module.
5. If all circuits test normal, replace the B16 backup lamp switch.

Backup Lamps Malfunction

1. Ignition OFF, disconnect the harness connector at the appropriate E5 backup lamp.
2. Ignition OFF, exterior lamps OFF, test for less than 5 Ω between the ground circuit terminal 3 and ground.
   • If greater than the specified range, test the ground circuit for an open/high resistance.
3. Connect a test lamp between the control circuit terminal 2 and ground.
4. Ignition ON, command the Backup Lamps ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states.
   • If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the K9 body control module.
   • 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 K9 body control module.
5. If all circuits test normal, replace the E5 backup lamp.