Circuit/System Description
WARNING: This page is about a different car, the 2007 Cadillac DTS. However, it is still accessible from the selected car via links, so may be relevant.
The memory seat module (MSM) controls the seat, recline, lumbar, and steering column motors via half bridges that are divided into 2 groups that are connected to separate power rails internal to the module.
Power rail 1 includes of the following motors:
- Seat front vertical motor
- Seat rear vertical motor
- Seat horizontal motor
- Seat recline motor
- Seat lumbar horizontal motor
Power rail 2 includes the following motors:
- Driver seat lumbar vertical motor
- Passenger seat lumbar vertical motor
- Steering column tilt actuator
- Steering column telescope actuator
The MSM connects all of the motor control circuits on each power rail to a common reference point whenever they are not in operation. This reference point is biased to approximately 2.5 volts. The MSM checks to see if this reference voltage is shorted to ground or battery before enabling any seat, lumbar, or steering column motor.