With A45

The memory lumbar support consists of the Memory Seat Module (MSM) and lumbar motors with a position sensor attached to each motor. The MSM controls the movement of the two lumbar motors. All the motors operate independently of each other.

The rear compartment fuse block BATT Fuse via CKT 1840 (ORN) supplies battery positive voltage (B+) to power the MSM. The LH MaxiFuse(R) block SEAT circuit breaker via CKT 742 (RED) provides battery positive voltage (B+) to the MSM which is used to run the motors. Ground for the MSM is provided via CKT 850 (BLK) to ground G302.

Motors
The lumbar motors are reversible. For example, the lumbar support is moved in and out by one motor. When the MSM receives an input to move the lumbar support in, it supplies battery positive voltage (B+) and ground to run the lumbar in/out motor to move the lumbar support in away from the driver's back. When it receives a lumbar out 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 the opposite direction, moving the lumbar support out towards the driver's back. The lumbar up/down motor is also powered this way. When the MSM receives an input from the LH lumbar switch, it supplies voltage to the appropriate lumbar motor.

The MSM provides each seat motor with a soft stop. The MSM 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.

Position Sensors
Position sensors are used by the MSM to store motor positions in memory and return the motors to the stored memory positions. The MSM provides a 5 volt reference voltage through CKT 788 (GRY) and reference ground through CKT 782 (BLK) to each of the lumbar 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 MSM or MMM to determine the motor position. The sensor feedback voltages vary from 0.25 volts to 4.75 volts. When a set memory command is executed, the MSM stores the motor positions by recording each position sensor feedback voltage. When a memory recall is commanded, the modules move the motors until all the position sensor feedback voltages equal the feedback voltages stored in memory.