GM Service Manual Online
For 1990-2009 cars only

The memory seat system consists of the seat adjuster memory module and 4 seat motors. The seat adjuster memory module controls the movement of the 3 seat position motors and one power recliner motor. All of the motors operate independently of each other.

The POWER SEATS circuit breaker in the body relay block supplies battery positive voltage (B+) in order to power the seat adjuster memory module via CKT 1440 (ORN). Ground for the seat adjuster memory module is provided via CKT 1350 (BLK) to G450.

Motors

The following 3 motors move the position of the seat:

    • Seat lateral motor
    • Seat rear height motor
    • Seat front height motor

Both of the height motors run simultaneously when the left seat switch is operated. These motors move the entire seat up and down. The seat recliner motor moves the angle of the seat back.

All of the motors are reversible. For example, the seat is moved forward and back by one motor. When the seat adjuster memory module receives an input to move the seat forward, the module supplies battery positive voltage (B+) and ground. This allows the module to run the motor and move the seat forward. When the module receives a seat back input, the seat adjuster memory module will supply power to the same motor, but the voltage and ground will be on the opposite motor cavities. The voltage polarity is reversed and the motor will run in the opposite direction, moving the seat back. All of the other seat motors are also powered in this manner.

Position Sensors

Position sensors are used by the seat adjuster memory module in order to store motor positions in memory and return the motors to the stored memory positions. The seat adjuster memory module provides a 5 volt reference voltage through CKT 569C (RED) and sensor ground through CKT 569D (BLK) to each of the seat position sensors. These sensors are potentiometers that are mounted to each motor's transmission cable. When the cable rotates, the resistance of the potentiometer varies and the feedback voltage is monitored by the seat adjuster memory module. This allows the module to determine the motor position. The sensor feedback voltage varies from 0.25-4.75 volts. When a set memory command is executed, the memory seat module stores the motor positions by recording each position sensor feedback voltage. When a memory recall is commanded, the module moves the motors until all of the position sensor feedback voltages equal the feedback voltages stored in memory.

Manual Movement

The seat adjuster memory module receives the seat manual movement inputs from the left seat adjuster switch. Battery positive voltage (B+) is supplied to the left seat switch from the POWER SEATS circuit breaker via CKT 1440 (ORN).

When a switch is actuated, battery positive voltage (B+) is supplied to the appropriate input of the seat adjuster memory module. The seat adjuster memory module supplies battery positive voltage (B+) to the appropriate motor(s) when one of the following inputs is received:

    • A lateral input
    • A rear height input
    • A front height input
    • A recline input

This condition causes the seat or seat back to move accordingly.

Memory Set

The seat adjuster memory module is capable of storing two seat positions in memory. The seat adjuster memory module will perform the following functions:

  1. Store the current driver seat position
  2. Assign the position to either switch 1 or switch 2 (or both switches) located on the seat

In order to store a position in the memory, perform the following steps:

  1. Adjust the seat to a desired position.
  2. Press the memory set switch. A chime confirmation will be heard.
  3. Press the desired switch (switch 1 or switch 2) within 5 seconds after pressing the memory set switch. A chime confirmation will be heard.
  4. The position is now stored in the memory. The position is now available for recall.

After a driver seat position is successfully stored, recall that position by pressing the appropriate memory position switch (switch 1 or switch 2).

The memory store feature is available in all of the ignition and start switch positions.

Memory Recall

The seat adjuster memory module is capable of recalling two driver seat positions.

The driver may recall a previously assigned driver seat position via switch 1 or switch 2.

In order to recall a position from the memory, perform the following steps:

  1. Press the desired switch (switch 1 or switch 2).
  2. A chime confirmation will be heard.
  3. The driver seat will begin to reposition if the vehicle conditions are correct.

If more than 3 seat adjustments are required, the adjustments will occur in the following order:

  1. The cushion will be adjusted in the height and lateral directions.
  2. The seat back will be adjusted in the recline position.

The memory recall feature is available in all of the ignition and start switch positions except for the CRANK position. A recall will be suspended if the ignition and start switch is turned to the CRANK position. The recall operation will complete when the ignition and start switch is returned to the RUN position.

If the ignition and start switch is in the RUN position, the transmission must be in PARK in order to recall a seat position.

A recall operation that is initiated when the required vehicle conditions are true will complete even if the vehicle conditions become false. For example, if a recall operation is initiated when the ignition and start switch is in the RUN position and the transmission is in PARK, the current recall operation will complete even if the transmission is shifted out of PARK. However, any further recall requests will be prohibited until the required vehicle conditions are present.

Cancelling a Memory Recall in Progress

The seat adjuster memory module will allow the driver to cancel a recall.

The driver may cancel a memory recall in progress by using one of the following methods:

  1. Activate any of the seat adjustment switches.
  2. Press the SET switch.
  3. Important: Pressing the memory switch that is NOT associated with the recall in progress will cause the seat to cancel the current recall operation and begin the recall operation for the new position requested. The vehicle conditions required for a recall must be present.

  4. Press the recall switch that is associated with the recall in progress (switch 1 or switch 2).