Memory Positioning Systems: Description and Operation

Circuit Operation

Memory Seat System Components
- Power Seat Switch
- Seat Horizontal Motor
- Seat Front Vertical Motor
- Seat Rear Vertical Motor
- Seat Recliner Motor
- Driver Seat Module
- Memory Seat Switch

Memory Seat System Description
Battery voltage is supplied to the driver seat module through the power seat circuit breaker. The driver seat module supplies the seat adjuster switch assembly with a battery positive reference voltage. While the seat adjuster switches are in an inactive state the switch contacts are closed to the adjuster switch ground circuit. When a seat adjuster switch is pressed to an active state the switch contact is closed to the reference voltage circuit. Battery voltage on a switch signal circuit indicates to the driver seat module the switch status is active. Each seat adjuster motor is controlled by the driver seat module through 2 motor control circuits. While the seat adjuster motors are in an inactive state the motor control circuits are closed to ground circuit contacts within the driver seat module. The driver seat module operates the seat adjuster motors by switching one of a motor s control circuits to battery voltage. The seat adjuster motors are bidirectional and the direction of adjuster motor rotation is determined by which of the adjuster motor control circuits is switched to battery voltage while the other remains grounded.

Memory Set/Recall Operation
The driver seat adjuster motors are equipped with potentiometer type position sensors used by the driver seat module to determine the seat position. The position sensors are supplied with 5 volt reference and ground circuits from the driver seat module. The position sensor signal circuits are referenced from ground within the driver seat module. The signal circuit voltage levels monitored by the driver seat module range from 0.39-4.58 volts and are determined by the wiper locations on the resistors within the motor position sensors. The position sensor circuit voltage levels are used by the driver seat module to determine the seat position when storing or recalling memory position settings.

The memory recall switch assembly on the driver s door provides inputs to the driver door module. Battery voltage is supplied to the memory recall switch assembly from the driver door module. When a memory recall 1, 2, or EXIT switch is pressed, the switch contacts close the appropriate switch signal circuit to the battery voltage supply circuit within the memory recall switch assembly. When the driver door module receives active switch signals from the memory recall switch assembly, the appropriate commands are sent to the driver seat module using the Class 2 Serial Data circuit.

Memory seat recall operation is allowed only with the transmission selector lever in the PARK position while the ignition is on. The transmission selector lever position data is provided to the driver seat module by a message through the Class 2 Serial Data circuit.