Automatic Climate Control
WARNING: This page is about a different car, the 2003 Saturn LW300, 2003 Saturn LW200, 2003 Saturn L300, and 2003 Saturn L200. However, it is still accessible from the selected car via links, so may be relevant.
The automatic climate control (ACC) system controls the heating, cooling, and ventilation in the vehicle. The ACC system will request air compressor over serial data from the heating, ventilation, and air conditioning (HVAC) control module to the body control module (BCM). The BCM will send the request on to the powertrain control module (PCM) or engine control module (ECM), if request is valid.