Circuit Description
WARNING: This page is about a different car, the 2006 Pontiac Montana SV6, 2006 Chevrolet Uplander, and 2006 Buick Terraza. However, it is still accessible from the selected car via links, so may be relevant.
The body control module (BCM) controls the RR defog relay. When the ignition switch is in RUN position and the operator has depressed the defogger switch, the BCM provides a ground signal on the rear defog relay control circuit energizing the relay.