HVAC Control Components: Notes
WARNING: This page is about a different car, the 2002 Pontiac Aztek and 2002 Buick Rendezvous. However, it is still accessible from the selected car via links, so may be relevant.
The HVAC Control Module is a class 2 device that interfaces between the operator and the HVAC system to maintain air temperature and distribution settings. The battery positive voltage circuit provides power that the control module uses for Keep Alive Memory (KAM). If the battery positive voltage circuit loses power, all HVAC DTCs and settings will be erased from KAM. The Body Control Module (BCM), which is the vehicle mode master, provides a device on signal.