Circuit/System Testing

Rear Fog Lamp Switch Malfunction

1. Ignition OFF, disconnect the harness connector at the turn signal/multifunction switch.
2. Ignition OFF, verify that a test lamp illuminates between B+ and the ground circuit terminal 3.
   • If the test lamp does not illuminate, test the ground circuit for an open/high resistance.
3. Ignition ON, verify that a test lamp does not illuminate between B+ and the signal circuit terminal 2.
   • If the test lamp illuminates, test the signal circuit for a short to ground. If the circuit tests normal, replace the IPM.
4. Install a 3 A fused jumper wire between the signal circuit terminal 2 and the ground circuit terminal 3. Verify the rear fog lamps are illuminated.
   • If the rear fog lamps do not illuminate, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the IPM.
5. If all circuits test normal, test or replace the turn signal/multifunction switch.

Rear Fog Lamps Malfunction

1. Ignition OFF, disconnect the rear fog lamp relay.
2. Ignition ON, verify that a test lamp does not illuminate between the control circuit terminal R35 and ground.
   • If the test lamp illuminates, test the control circuit for a short to voltage.
3. Verify that a test lamp illuminates between the B+ circuit terminal R32 and ground.
   • If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance. If the circuit tests normal and the B+ circuit fuse is open, test the control circuit terminal R32 for a short to ground. If the circuit tests normal, test or replace the rear fog lamp relay.
4. Ignition ON, verify that a test lamp illuminates between the B+ circuit terminal R31 and ground.
   • If the test lamp does not illuminate, test the B+ circuit for an open/high resistance.
5. Disconnect the harness connector at the inoperative rear fog lamp.
6. Ignition OFF, scan tool OFF, exterior lamps OFF, test for less than 5 ohms between the ground circuit terminal B and ground.
   • If greater than the specified range, test the ground circuit for an open/high resistance.
7. Connect the harness connector at the inoperative rear fog lamp.
8. Connect a 15 A fused jumper wire between the B+ circuit terminal R32 and the control circuit terminal R33. Verify the rear fog lamps are activated.
   • If the rear fog lamps do not activate, test the control circuit terminal R33 for an open/high resistance. If the circuit tests normal, test or replace the inoperative rear fog lamp.
9. Connect a test lamp between the B+ circuit terminal R31 and the control circuit terminal R35
10. Command the Rear Fog lamps ON and OFF with the 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 ground. If the circuit tests normal, replace the RIM.
    • If the test lamp is always OFF, test the control circuit for a short to voltage or open/high resistance. If the circuit tests normal, replace the RIM.
11. If all circuits test normal, test or replace the rear fog lamp relay.