Circuit Description
WARNING: This page is about a different car, the 2003 Oldsmobile Bravada, 2003 GMC Envoy XL, 2003 GMC Envoy, and 2003 Chevrolet TrailBlazer. However, it is still accessible from the selected car via links, so may be relevant.
When the BCM receives a voltage signal from the backup lamp switch requesting to illuminate the backup lamps, battery voltage is sent directly from the BCM through the backup lamp supply voltage circuit to the backup lamps.