Circuit/System Testing
WARNING: This page is about a different car, the 2008 GMC Sierra, 2008 GMC Cab & Chassis Sierra, 2008 Chevrolet Silverado, and 2008 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.
- Ignition OFF, remove the fog lamp relay in the underhood fuse block.
- Ignition ON, test for voltage at the relay control circuit terminal 86 of the underhood fuse block.
- If voltage is present, test the control circuit for a short to voltage. If all circuits/connections test normal, replace the fog lamp relay.
- If voltage is not present, replace the BCM.