comfort system. Controller. ONBOARD POWER SUPPLY. An electronic control unit that monitors and controls various electronic systems in a vehicle's body, and communicates with other on-board computers via the car's vehicle bus. BCM-2. From 06/21/2010. Module to control HVAC functions. To 06/21/2010. Body Control Computer (BCC). Central Timer (CTM). Climate Control. CONTOUR UNIT. Controller. Generic Electronic Control (GEM). HVAC Control.