Circuit Description
WARNING: This page is about a different car, the 2006 Chevrolet Monte Carlo and 2006 Chevrolet Impala. However, it is still accessible from the selected car via links, so may be relevant.
When the body control module (BCM) receives a ground signal from the headlamp dimmer switch high beam signal or flash to pass (FTP) switch signal commanding to illuminate the high beam headlamps, the BCM will energize the high beam relay by grounding the high beam relay control circuit.