Power Seats System (with A45 Disabled)

Power Seats System Description and Operation (with A45 Disabled)

The driver power seat system with a non-memory configured memory seat module (MSM) consists of the following components:

* Memory Seat Module
* Seat Adjuster Switch
* Seat Horizontal Motor
* Seat Front Vertical Motor
* Seat Rear Vertical Motor
* Seat Recline Motor
* PWR Seat Circuit Breaker 30 A
* MEM T&T Fuse 10 A

Non Memory MSM and IPM

The non-memory version of the driver power seat still includes the memory seat module (MSM). The RPO codes for seating are A45 for memory and AL2 for lumbar. The instrument panel module (IPM) contains a configuration frame for the vehicle RPOs and is configured according to RPO content. In order for the MSM to determine the memory configuration it looks for 2 signals, via GMLAN, from the IPM to determine the seating RPO content. These signals are Memory Seat Present (A45) and Memory Lumbar Present (AL2). When these signals are FALSE, the seat is non memory, and the MSM will not look for inputs from the seat position sensors. However; sense the MSM controls the steering column, it always looks for column position sensor inputs. Refer to Steering Wheel and Column Description and Operation (Description and Operation).

Seat Adjuster Switch

Battery positive is supplied at all times to the seat adjuster switch from the MEM T&T Fuse located in the rear fuse block. When the power seat switches are pressed they send a 12-volt signal to the memory seat module (MSM). The MSM commands the selected seat motor to move in response to the switch inputs.

MSM Power and Grounds

Battery positive voltage is supplied at all times to the memory seat module (MSM) from the PWR SEAT Circuit Breaker located in the rear fuse block. This voltage is used to power up MSM and also to apply power to the seat motors when commanded. Battery positive is also supplied to the MSM from the MEM T&T Fuse located in the rear fuse block. The MSM monitors this voltage to determine the state of power at seat adjuster switch. If voltage is not detected from this circuit, the MSM will cancel or disable all memory recall functions. Ground is provided to the module through the ground circuit and G 307.

Seat Motors

The memory seat module (MSM) controls the movement for each of the seat directional motors and the 2 lumbar motors. Refer to Lumbar Support Description and Operation (Without Memory A45) (Lumbar Support (Without Memory A45))Lumbar Support Description and Operation (With Memory A45 Disabled) (Lumbar Support (With Memory A45 Disabled))Lumbar Support Description and Operation (With Memory A45 Enabled) (Lumbar Support (With Memory A45 Enabled)). All of the motors operate independently of each other. Each motor contains a electronic circuit breaker (PTC), which will reset only after voltage has been removed from the motor.

There are 4 motors that move the position of the seat. These are the seat horizontal motor, front vertical motor, rear vertical motor and the recline motor. The horizontal motor moves the entire seat forward and rearward. Both vertical motors can run simultaneously when the seat switch is operated in order to move the entire seat up and down. Or they can be selected independently to vertically tilt the front or rear of the seat up and down. The recline motor moves the angle of the seat back forward or rearward.

All seat motors are reversible. For example, when a seat switch is pressed to move the entire seat forward, battery positive voltage is applied through the power seat horizontal forward switch signal circuit to the MSM. In response to this signal, the MSM applies battery positive voltage through the driver seat horizontal motor forward control circuit and ground through the driver seat horizontal motor rearward control circuit to the motor. The motor runs in order to drive the entire seat forward. Moving the entire seat rearward works similarly to moving the entire seat forward, except that battery positive voltage and ground are applied on the opposite circuits causing the motor to run in the opposite direction. All of the seat motors are powered this way.

Soft stop functions are not used for driver seat motors that are controlled by either a memory or non-memory MSM. However, soft stop functions are used for the MSM controlled steering column motors. Refer to Steering Wheel and Column Description and Operation (Description and Operation).