Body Control Systems: Description and Operation

MODULE CONTROLLED FUNCTIONS

The vehicle is equipped with the following multifunction modules:
- Air suspension module
- Driver door module (DDM)
- Driver seat module (DSM)
- Lighting control module (LCM)

Air Suspension Module
The air suspension module monitors the inputs and provides outputs and diagnostic information for the following systems:
- Vehicle dynamic suspension
- Variable assist power steering (VAPS)

The air suspension module provides the instrument cluster with a ground circuit in order to illuminate the air suspension warning indicator in the instrument cluster and also receives door ajar information from the DDM. The air suspension module controls the VAPS actuator on the power steering gear which increases or decreases the power steering assist depending on the vehicle speed received on a dedicated vehicle speed circuit hardwired from the powertrain control module (PCM).

Driver Door Module (DDM)
The DDM monitors the inputs and provides outputs and diagnostic information for the following multiple vehicle systems:
- Power door locks
- Power mirrors
- Remote keyless entry (RKE) system

The DDM monitors all of the door ajar switches which are hardwired to the module. This door ajar information is sent to the air suspension module on a single hardwired circuit. Diagnostic information is retrieved from the DDM on the standard corporate protocol (SCP) communication network. The power door locks, power mirrors and the RKE system are all controlled by the DDM. If equipped with memory seats, the seat adjust switch provides inputs to the DDM, which sends this information to the DSM over the SCP network. If not equipped with a power luggage compartment lid, the DDM receives an input from the luggage compartment lid release switch and operates the luggage compartment lid release solenoid. If equipped with a power luggage compartment lid, the DDM sends a signal to the luggage compartment lid module, which will operate the luggage compartment lid release solenoid.

Driver Seat Module (DSM)
The DSM receives the seat adjust switch input information over the SCP network communication from the DDM and operates the seat motors to the desired position. The DSM monitors the seat position and adjustable pedal sensors to determine how long to operate each specific seat motor and adjustable pedal motor when the memory function is being commanded. The DSM is only on vehicles equipped with memory seats and memory adjustable pedals.

Lighting Control Module (LCM)
The LCM monitors the inputs and provides outputs and diagnostic information for the following multiple vehicle systems:
- Brake shift interlock
- Exterior lighting
- Interior lighting
- Perimeter alarm

The LCM receives a voltage input from the brake pedal position switch and provides power to the brake shift interlock solenoid. For the exterior lighting, it receives inputs and provides outputs to control the exterior, interior (including the cluster and panel illumination) lighting systems on the vehicle. The perimeter alarm is controlled by the LCM, which receives inputs from the perimeter alarm switches and arms the alarm when commanded.

Rear Audio/Climate Control Module
The rear audio/climate control module monitors the inputs and provides information for the following multiple vehicle systems:
- Rear audio
- Rear climate control

The rear audio/climate control module receives a variable resistance input from the rear audio/climate control switch to determine the level of rear audio volume, rear climate control temperature and fan speed.