Circuit/System Verification

WARNING: This page is about a different car, the 2009 GMC Sierra, 2009 GMC Cab & Chassis Sierra, 2009 Chevrolet Silverado, and 2009 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.

Ignition ON, observe the scan tool parklamp switch parameter while cycling the headlamp switch between the park and off positions. The parameter should cycle between active and inactive.
- If the parameter does not cycle between the specified values, refer to Park Lamp Switch Circuit Test .
Connect a test lamp between the relay side of a park lamp fuse and ground.
Command the parking lamps on and off with a scan tool. Verify that the test lamp turns on and off while switching between the commanded states.
- If the test lamp does not turn on and off while changing between the commanded states, refer to the Park Lamp Relay Circuit Test .
If any of the park, marker, license, or tail lamps do not turn on and off, refer to Exterior Lamps Circuit Test .