The memory seat system consists of the following components:

The memory seat module (MSM) cannot perform memory recall functions unless the Personalization Option is activated. The personalization option is located in the dash integration module (DIM). The DIM reports the personalization option setting to the MSM, as well as other receiving modules, via a class 2 message each time the ignition switch is cycled to the ON position. The MSM will then store the personalization option setting and examine it before making a memory seat adjustment. The personalization option setting stored within the MSM will not change until the personalization option setting in the DIM is changed and the ignition switch is cycled to the ON position.

Battery positive voltage is supplied at all times to the seat adjuster switch from the MEM Fuse located in the rear fuse block. When the seat switches are pressed they send a 12-volt signal to the MSM. The MSM commands the selected seat motors to move in response to the switch signal.

Battery positive voltage is supplied at all times to the MSM through the battery positive voltage circuit 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. The MSM is grounded through the module ground circuit and G 301.

The MSM controls the movement of each of the above mentioned seat directional motors and the 2 lumbar motors. Refer to Lumbar Support Description and Operation . All of the seat 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 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 and rearward.

All motors are reversible. For example, when the seat adjuster switch is operated to moved the entire seat forward, battery positive voltage is applied through the entire seat 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 motor is grounded through the driver seat horizontal motor rearward control circuit to the motor. 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 the physical travel limit.

The seat position sensors are potentiometers which are either attached directly to the motor's transmission cable or are an internal part of the motor. The 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 volts to 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.

When a memory function switch is pressed, the associated signal circuit of the driver's door switch assembly (DDSA) is momentarily grounded. In response to this signal, the DDSA then sends a message via the simple bus interface to the driver door module (DDM) indicating that a memory function signal has been received. The DDM then sends the message to the MSM via the class 2 serial data line.

The current seat position may be recorded for 2 different drivers. To record a position, adjust the drivers seat including the lumbar support to a comfortable position, then press and hold button 1 for 5 seconds, a double beep will sound each time a memory position is set. A second seat position may be programmed by repeating the above steps and pressing button 2. When the MSM receives a memory set message, the MSM records the feedback voltages from the position sensors for the appropriate driver. The easy exit position is programmed by moving the seat to the desired exit position and then holding the exit button for 5 seconds. Two easy exit positions can be programmed, one for each driver. When the MSM receives a set exit message, the MSM records the feedback voltages from the four seat position sensors for the appropriate driver. The lumbar support is not involved in the easy exit function.

When the memory recall 1 or 2 button is pressed, a single chime is sounded through the radio in order to acknowledge the signal and the MSM receives the memory recall message. In response to this message, the MSM applies battery positive voltage to the motors until the position sensor feedback voltages equal the feedback voltages stored in memory for the appropriate driver. When the EXIT button is pressed, a single chime is sounded in order to acknowledge the signal and the MSM receives the easy exit message. In response to this message, the MSM applies battery positive voltage to the seat motors until the position sensor feedback voltages equal the feedback voltages stored in memory for the appropriate driver.

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

When a keyless entry transmitter is used in order to unlock the vehicle doors, the remote keyless entry (RKE) module communicates the unlock command and which driver performed the command to the MSM via a class 2 message. There are 2 personalized recall options when the MSM receives an unlock message:

The memory seat module 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 the PARK position, only the recall personalization function is deactivated and 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, only memory record is allowed, all other memory seat functions are not allowed.