Originally Posted by rrounds
What is a Body Control Module and what does it do
Basically, it'* a vehicle computer. In the 2K+ Bonneville there are several, all which work together control virtually every vehicle function from dimming the interior lights to controlling the rear defroster and much much more. Many vehicles only have one. BCM is a more general term but ultimately can refer to a single module or any individual module (even though in multi module vehicles there is a specific reference for each).
In the 2K+ Bonneville, there is:
DIM - Dash Integration Module
Controls headlights and exterior lights, horn, interior incandescent dimming, power moding over the class 2 data bus, steering wheel controls and storage of clock settings.
RIM - Rear Integration Module
Automatic Level Control, fuel door lock control, heated seat controls, rear defogger, retained accessory power, reverse lamps and various interior light functions.
IPM - Instrument Panel Integration Module
Ambient light sensor / twilight delay, front HVAC air delivery and temp control, many interior lamp related functions, input device for T/C and trunk lid switches.
Each of the above modules has functions which I haven't listed, simply because there are so many. The term "Body" refers to anything related to body functions in the vehicle (as opposed to PCM which is powertrain control).