Liftgate Module (LGM)
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.
Rear Defog Requested: The scan tool displays Yes/No. When the rear window defogger switch is depressed, the HVAC control module sends a class 2 message to the LGM to enable the rear window defogger. The LGM enables the rear window defogger, which the scan tool displays as Yes.