Circuit/System Testing
WARNING: This page is about a different car, the 2010 Saturn Outlook, 2010 GMC Acadia, 2010 Chevrolet Traverse, and 2010 Buick Enclave. However, it is still accessible from the selected car via links, so may be relevant.
- Ignition OFF, disconnect the RR DEFOG relay.
- Test for less than 1 ohm between the ground circuit terminal 85 and ground.
- If greater than the specified range, test the ground circuit for an open/high resistance
- Connect a test lamp between the control circuit terminal 86 and the ground circuit terminal 85.
- Ignition ON, command the Rear Defog Request 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 HVAC 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 HVAC control module.
- If all circuits test normal, test or replace the RR DEFOG relay.