Circuit Description
WARNING: This page is about a different car, the 2004 Pontiac Grand Prix. However, it is still accessible from the selected car via links, so may be relevant.
The BCM controls the Rear Window Defogger relay circuit. When the ignition switch is in Run position and the operator has depressed the defogger switch, the BCM provides battery negative voltage to the Rear Window Defogger relay control circuit and the Electronic Compass module. The Electronic Compass module translates the signal to Compass Data which is then transmitted to the DIC for display of the Rear Defogger mode.