Body Control Systems: Description and Operation

Body Control System Description and Operation

The body control system consists of the body control module (BCM) and its associated controls. Battery positive voltage is provided to the BCM from the TURN/HAZ fuse and the CHMSL/BKUP fuse in the fuse block instrument panel (I/P). The module grounds are wired to ground G200, G201 and G301. The BCM is wired to the class 2 serial data communication bus as well as discrete input and output terminals to control the functions of the vehicles body.

Power Mode Master

This vehicles BCM functions as the Power Mode Master (PMM). Refer to Power Mode Description and Operation (Power Mode Description and Operation) for a complete description of the power mode functions.

Body Control Module

The various body control module (BCM) input and output circuits are described in the corresponding functional areas indicated on the BCM electrical schematics. The BCM functions include the following:

* Battery rundown protection-Inadvertent power-Refer to Interior Lighting Systems Description and Operation (Interior Lighting Systems Description and Operation).
* BTSI/automatic transmission shift lock control-Refer to Automatic Transmission Shift Lock Control Description and Operation (LS4/5.3L) (Automatic Transmission Shift Lock Control Description and Operation (LS4/5.3L))Automatic Transmission Shift Lock Control Description and Operation (L26/L32/3.6L) (Automatic Transmission Shift Lock Control Description and Operation (L26/L32/3.6L)).
* Bulb check-Refer to Instrument Cluster Description and Operation (Description and Operation).
* Chimes-Refer to Audible Warnings Description and Operation (Audible Warnings Description and Operation).

- Check gages
- Content theft deterrent
- Door ajar warning
- Headlamps ON
- Key-in-ignition
- Oil reset
- Park brake warning
- Seat belt not fastened
- Turn signal ON
- Vehicle theft deterrent

* Door lock interface-Refer to Power Door Locks Description and Operation (Description and Operation).
* Exterior and interior lighting control-Refer to Exterior Lighting Systems Description and Operation (Exterior Lighting Systems Description and Operation).

- Automatic lighting control
- Backup lamps
- Daytime running lights (DRL)
- Fog lamps
- High/low beam head lamps
- Park brake lights
- Turn hazard lamps

* Gage control-Refer to Instrument Cluster Description and Operation (Description and Operation).
* Heated seats-Refer to Heated Seats Description and Operation (Description and Operation).
* Horn interface-Refer to Horns System Description and Operation (Description and Operation).
* Instrument cluster indicator control-Refer to Instrument Cluster Description and Operation (Description and Operation).
* Interior lighting-Refer to Interior Lighting Systems Description and Operation (Interior Lighting Systems Description and Operation).
* Key-in-ignition sensing-Refer to Audible Warnings Description and Operation (Audible Warnings Description and Operation).
* Parking brake state sensing-Refer to Brake Warning System Description and Operation (Brake Warning System Description and Operation).
* Retained accessory power (RAP)-Refer to Retained Accessory Power (RAP) Description and Operation (Retained Accessory Power (RAP) Description and Operation).
* Rear compartment interface-Refer to Power Door Locks Description and Operation (Description and Operation).
* Rear defogger-Refer to Rear Window Defogger Description and Operation (Rear Window Defogger Description and Operation).
* Remote function control-Refer to Keyless Entry System Description and Operation (Description and Operation).
* RFA communication link-Refer to Keyless Entry System Description and Operation (Description and Operation).
* Seat belt use sensing-Refer to Seat Belt System Description and Operation (Description and Operation).
* Theft deterrent vehicle/content-Refer to Content Theft Deterrent (CTD) Description and Operation (Content Theft Deterrent (CTD) Description and Operation) or Immobilizer Description and Operation (Immobilizer Description and Operation).
* Washer solvent level sensing-Refer to Wiper/Washer System Description and Operation (Description and Operation).
* Wiper/washer-Refer to Wiper/Washer System Description and Operation (Description and Operation).