Circuit/System Testing
WARNING: This page does not describe the selected car, but rather 8 other vehicles, including the 2007 GMC Yukon XL, 2007 GMC Yukon, 2007 Chevrolet Tahoe, 2007 Chevrolet Suburban, and 2007 Chevrolet Avalanche. However, it is still accessible from the selected car via links, so may be relevant.
- Ignition OFF, disconnect the C2 harness connector at the underhood fuse block.
- Connect a test lamp between the control circuit terminal 27 and ground.
- Command the Wiper Relay 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, test or replace the body control module.
- If the test lamp is always OFF, test for a short to ground or an open/high resistance on the control circuit. If the circuit tests normal, test or replace the body control module.
- If all circuits test normal, test or replace the underhood fuse block.