Circuit/System Testing

Backup Lamp Switch Malfunction

1. Ignition OFF, exterior lamps OFF, all doors closed, disconnect the harness connector at the B16 backup lamp switch. It may take up to 2 minutes for all vehicle systems to power down.
2. Test for less than 5Ω between the ground circuit terminal 2 and ground.
   • If 5Ω or greater 
   1. Ignition OFF.
   2. Test for less than 2Ω in the ground circuit end to end.
      • If 2Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2Ω, repair the open/high resistance in the ground connection.
   • If less than 5Ω 
3. Ignition ON.
4. Verify the scan tool Reverse Position Switch parameter is Off.
   • If not Off 
   1. Ignition OFF, disconnect the X2 harness connector at the K20 engine control module.
   2. Test for infinite resistance between the signal circuit terminal 1 and ground.
      • If less than infinite resistance, repair the short to ground on the circuit.
      • If infinite resistance, replace the K20 engine control module.
   • If Off 
5. Install a 3A fused jumper wire between the signal circuit terminal 1 and the ground circuit terminal 2.
6. Verify the scan tool Reverse Position Switch parameter is On.
   • If not On 
   1. Ignition OFF, disconnect the X2 harness connector at the K20 engine control module, ignition ON.
   2. Test for less than 1V between the signal circuit terminal 1 and ground.
      • If 1V or greater, repair the short to voltage on the circuit.
      • If less than 1V
   3. Test for less than 2Ω in the signal circuit end to end.
      • If 2Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2Ω, replace the K20 engine control module.
   • If On 
7. Test or replace the B16 backup lamp switch.