Test Description
WARNING: This page is about a different car, the 2003 GMC Sierra, 2003 GMC Cab & Chassis Sierra, 2003 Chevrolet Silverado, and 2003 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.
The numbers below refer to the step numbers on the diagnostic table.
2. Listen for an audible click when the high beam relay operates. Command both the ON and OFF states. Repeat the commands as necessary.
3. Tests for voltage at the coil side of the high beam relay.
4. Verifies that the body control module (BCM) is providing ground to the high beam relay.
5. Tests if ground is constantly being applied to the high beam relay.
6. Tests if there is opposing voltage present or an open high beam relay control circuit.
12. After replacement of the BCM you must calibrate the new module for proper operation.