The memory seat system consists of the memory seat/mirror module and 4 seat motors. The memory seat/mirror module controls the movement of the three seat position motors and one seatback recline motor. All the motors operate independently of each other.

The RH rear fuse block PWR STS circuit breaker via CKT 1340, ORN, supplies battery positive voltage (B+) to power the memory seat/mirror module. Ground for the memory seat/mirror module is provided via CKT 150, BLK, to ground G202.

The following 3 motors move the position of the seat:

Both the vertical motors run simultaneously when the LH seat switch is operated. These motors move the entire seat up and down. The recline motor moves the angle of the seatback.

All motors are reversible. For example, the seat is moved forward and back by one motor. When the memory seat/mirror 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 MSM 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 other seat motors are also powered this way.

Position sensors are used by the memory seat/mirror module in order to store motor positions in memory and return the motors to the stored memory positions. The memory seat/mirror module provides a 5 volt reference voltage through CKT 788, GRY, and reference ground through CKT 782, BLK, to each of the seat position sensors. These sensors are potentiometers which 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 memory seat/mirror module. This allows the module to determine the motor position. The sensor feedback voltages vary from .25 volts to 4.75 volts. When a set memory command is executed, the memory seat/mirror 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. For the easy exit functions, only seat position sensor feedback voltages are recorded and only the seat motors run.

The memory seat/mirror module receives the seat manual movement inputs from the LH seat switch. Battery positive voltage (B+) is supplied to the LH seat switch as follows:

When a switch is actuated, battery positive voltage (B+) is supplied to the appropriate input of the memory seat/mirror module. When a horizontal, rear vertical, front vertical, or recline input is received, the MSM supplies battery positive voltage (B+) to the appropriate motor(s). This causes the seat or seatback to move accordingly.

On Oldsmobile vehicles, the memory seat/mirror module receives the inputs from the LH seat/lock switch. On Buick vehicles, the memory seat/mirror module receives the inputs from the outside mirror switch. The current seat positions may be recorded for 2 different drivers. In order to record the current positions, press the MEMORY SET button. This is followed by a chime that acknowledges the input. Within 5 seconds, press either the DRIVER-1 or DRIVER-2 button. When the memory seat/mirror module receives these inputs, the module records the feedback voltages from the four seat position sensors for the appropriate driver. A single chime is sounded in order to acknowledge that the position was recorded. A memory set function can be performed at any time.

When the DRIVER-1 or DRIVER-2 button is pressed the memory seat/mirror module receives the input and a single chime is sounded. The memory seat/mirror module supplies battery positive voltage (B+) to the seat motors. This is done until all of the seat position sensor feedback voltages equal the feedback voltages stored in the memory for the appropriate driver.

Battery positive voltage (B+) is supplied simultaneously to the memory seat/mirror module memory 1 and memory 2 inputs when one of the following actions occurs:

This action signals the easy exit function. In response, the memory seat/mirror module will move the seat to the fully down and back position. The module supplies battery positive voltage (B+) to the LH seat front vertical, LH seat rear vertical, and the LH seat horizontal motors. The voltage is supplied until the seat is fully back and down. The recline motor is not moved during this operation.

Memory recall and easy exit functions may only be performed if one of the following situations exists:

When a keyless entry transmitter is used to unlock the vehicle's doors, the remote function actuator (RFA) module communicates the following information to the memory seat/mirror module:

This communication is performed via CKT 1985, PPL. Refer to Keyless Entry Schematics .

Each keyless entry transmitter is programmed with one of the 4 personalized recall options when the RFA receives an unlock message:

Program a keyless entry transmitter for a specific mode as follows:

In order to enter the manual diagnostic modes of the memory seat/mirror module, the ignition switch must be in the OFF position. If the ignition is set to the RUN or START positions while the module is in a diagnostic mode, the module will exit diagnostics and sound 3 chimes.

Mode 1 diagnostics of the memory seat/mirror module is used in order to test all memory, seat and mirror switch inputs. In order to enter mode 1 of the manual diagnostics, the memory seat/mirror diagnostic connector must be grounded. The diagnostic connector may be taped into the harness. When the connector is grounded, the module will chime once in order to acknowledge entrance into mode 1 diagnostics. This connector must remain grounded throughout mode 1 diagnostics. If ground at the connector is lost for more than 5 seconds, then the module will exit diagnostics and sound 3 chimes. All memory, seat and mirror functions are disabled during mode 1. In order to test the inputs, the memory, seat or mirror switch is operated as if performing that function. Each time the memory seat/mirror module sees an input from a switch, the module chimes once. If a switch is operated and the module does not chime, the module did not receive the input. This may indicate a problem with the switch or the wiring from the switch to the module.

Mode 2 diagnostics is used in order to test the seat and mirror position sensor inputs. In order to enter mode 2 of the manual diagnostics, while in mode 1 diagnostics, the ground is removed from the memory seat/mirror diagnostic connector and then reapplied within 5 seconds. The module will then chime twice in order to acknowledge that the module has entered mode 2 diagnostics. Again, if ground at the connector is lost for more than 5 seconds, the module will exit diagnostics and sound three chimes. In order to test the inputs, the LH seat switch or outside mirror switch is operated to command the seat or mirror to move and the position sensor input for that direction is tested. For example, if the seat is commanded to move forward, the module will test the horizontal position sensor. If the module sounds a chime when a switch is being operated, then the module senses a discontinuity in that direction's position sensor. That means there may be a problem with the position sensor or the wiring from the module to the position sensor.

In order to exit the diagnostic mode, either remove the ground from the memory seat/mirror module diagnostic connector for more than 5 seconds or turn the ignition to the RUN or START position. When the module exits the diagnostic mode, the module will sound 3 chimes in order to acknowledge that it is no longer in diagnostic mode.