The memory seat system consists of the following components:

The MSM is referenced in the Tech 2 as the driver position module (DPM).

Battery positive voltage is supplied at all times to the seat adjuster switch from the TILT/TELE SW/MEM SEAT MOD S Fuse located in the body control module (BCM) fuse block. When a seat switch is pressed, battery positive voltage is applied through the switch contacts and the switch signal circuit to the MSM. The MSM then commands the selected seat motor to move in response to the switch signal.

Battery positive voltage is supplied at all times to the memory function switch from the TILT/TELE SW/MEM SEAT MOD Fuse located in the body control module (BCM) fuse block. When a memory recall switch is pressed battery positive voltage is applied through the switch contacts and the switch signal circuit to the memory seat module (MSM). The MSM then commands the appropriate seat motors to move to the pre-recorded seat position stored in memory in response to the switch signal.

Battery positive voltage is supplied at all times to the memory seat module (MSM) through the battery positive voltage circuit from the POWER SEATS circuit breaker located instrument panel (I/P) fuse block. This voltage is used to power up MSM and also to apply power to the seat motors when commanded. Battery positive voltage from the TILT/TELE SW/MEM SEAT MOD Fuse located in the body control module (BCM) fuse block that supplies voltage to the seat adjuster switch and the memory function switch, also supplies voltage to the MSM. The MSM monitors this voltage circuit in order to determine if battery voltage is supplied to the seat adjuster switch. The MSM is grounded through the module ground circuit and G301.

The memory seat module (MSM) controls the movement of each of the above mentioned seat directional motors. All of the seat motors operate independently of each other. Each motor contains a electronic circuit breaker (PTC), that opens in the event of a circuit overload and will reset only after voltage has been removed from the circuit.

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. The seat vertical motors may operate independently to tilt the front or rear of the seat cushion up or down. Both vertical motors can also run simultaneously to move the entire seat up or down. The recline motor moves the angle of the seat back forward or rearward.

All motors are reversible. For example, when the seat switch is operated to moved the entire seat forward, battery positive voltage is applied through the horizontal forward switch contacts and 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 to the horizontal motor. The MSM supplies ground to the motor through the driver seat horizontal motor rearward control circuit. The motor runs to drive the entire seat forward until the switch is released. 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 other seat motors are also powered this way.

The MSM provides each seat motor with a soft stop. The module will actually stop the motor just before the physical end-of-travel for that motor. This decreases the stress on each motor. If a motor reaches the end-of-travel due a soft stop and the seat switch is released and then activated again, the seat will move a short distance farther to it's physical travel limit.

The seat position sensors are potentiometers which are either attached directly to the motor transmission cable or are an internal part of the motor. The memory seat module (MSM) supplies a 5-volt reference voltage through the 5-volt reference circuit and ground through the low reference circuit to the respective seat position sensors. When the motor or cable rotates, the resistance of the potentiometer varies changing the feedback voltage of the position sensor signal circuit. This voltage varies from 0.25-4.75 volts. The MSM monitors this voltage signal to determine the position of the seat.

When a memory set command is received, the MSM records the seat position by storing the feedback voltage from each position sensor. Then, when a memory recall command is received, the MSM moves the motors until the position sensor feedback voltages equals the feedback voltages stored in memory.

After the driver door switch assembly (DDSA) receives a memory request signal from the memory function switch, it forwards the memory request via class 2 serial data line to the memory seat module (MSM). The MSM then examines the request and inspects to see if it has received any messages from any of the other vehicle modules that would prohibit seat movement. If no prohibited messages have been received, the MSM will then move the seat to the appropriate position per the memory request.

The current seat position may be recorded for 2 different drivers. To record a position, adjust the drivers seat to a comfortable position, then press and hold button 1 until a chime is heard. A second seat position may be programmed by repeating the above steps and pressing button 2. When the MSM receives a memory set message, it records the feedback voltages from all 4 seat position sensors for the appropriate driver. The easy exit position is programmed by moving the seat to the desired exit position and then press and hold the exit button until the chime is heard. Two easy exit positions can be programmed, one for each driver. When the MSM receives a set exit message, it records the feedback voltages from all 4 seat position sensors for the appropriate driver.

Memory recall will not work if the shift lever is out of NEUTRAL (N) or PARK (P).

Specific drivers are recognized by the vehicle through the keyless entry transmitters. When the transmitter is used in order to unlock the vehicle doors, it sends a radio frequency to the remote control door lock receiver (RCDLR). The RCDLR interprets the signal, then communicates the unlock command and which driver performed the command via a class 2 message over the serial data line to the appropriate modules and the memory seat module (MSM). The MSM will then recall any previously programed personalization easy exit or memory seat positions. For more information concerning the programing of the personalization feature refer to the owners manual.

The memory seat module (MSM) receives the ignition switch signal and the gear selector position via class 2 messages. When the ignition switch is in the OFF position, memory record, memory recall, personalization recall, and exit recall functions are all allowed. When the ignition switch is in the ON position and the gear selector is in PARK, the personalization recall function is deactivated, while all other memory functions are allowed. When the ignition switch is in the ON position and the gear selector is out of the PARK position, all memory seat recall functions are inhibited, only memory set is allowed.

After an air bag deployment, the sensing and diagnostic module (SDM) will send out a post air bag deployment signal via the class 2 serial data line. After receiving this message, the MSM will inhibit all memory recall functions, or cancel any memory recall function in process.