Lumbar Support Description and Operation (AM3 W/RPO Code A45)

LUMBAR SUPPORT DESCRIPTION AND OPERATION (AM3 WITH A45)

LUMBAR MASSAGE COMPONENTS
The driver massaging lumbar system consists of the following components:
- Lumbar Switch
- Lumbar Massage Module
- Memory Seat Module (MSM)
- Lumbar Vertical Motor
- Lumbar Vertical Position Sensor
- PWR SEAT Circuit Breaker 30 A
- MEM T&T Fuse 10 A

POWER SUPPLY
Battery positive voltage is supplied at all times to the lumbar switch through the battery positive circuit and the MEM T&T Fuse located in the rear fuse block. Battery positive voltage is also supplied at all times to the massage module through the battery positive voltage circuit and the PWR SEAT Circuit Breaker located in the rear fuse block. Ground is supplied to the massage module through the module ground circuit and G 302.

LUMBAR VERTICAL MOTOR
The lumbar vertical motor is reversible. When commanded, it will move the lumbar support in the up and down directions. To protect itself, the motor contains a electronic circuit breaker (PTC) that opens in the event of a circuit overload and will reset only after voltage has been removed from the circuit. The lumbar vertical motor also contains a sensor to monitor the lumbar position. The lumbar vertical motor is controlled by the massage module during massage operation only. During memory recall and manually controlled operations, it is controlled by the MSM.

MASSAGE OPERATION
When the top of the lumbar switch is momentarily pressed where it is marked AUTO in order to initiate the massage function, battery positive voltage is momentarily applied through the switch contacts and the seat lumbar up switch signal circuit to the massage module. In response to this signal, the massage module then cycles battery positive voltage and ground through the lumbar motor up and down control circuits to the motor. The motor will then continuously move the lumbar support 50 mm in both the up and down directions, and will continuously run this way for 10 minutes or until the lumbar switch is pressed to cancel operation. When massage operation has ceased, the massage module will return the lumbar support to the position from which massage was initiated.

During massage operation, the lumbar horizontal support can be adjusted without interruptions to the massage cycle by operating the lumbar switch in either the forward or rearward directions. However, manually moving the lumbar vertical switch in either the up or down directions will cancel the massage operation and move the lumbar support in the desired direction.

MANUAL VERTICAL MOVEMENT
When the lumbar switch is operated to move the lumbar support up, battery positive voltage is applied through the lumbar up switch contacts and the lumbar up switch signal circuit to the massage module. In response to this signal, the massage module applies battery positive voltage through the driver seat lumbar up signal circuit to the MSM. The MSM then applies battery positive voltage through the seat lumbar motor up control circuit back to the massage module. The massage module, in turn, applies battery positive voltage through the lumbar motor up control circuit and ground through the lumbar motor down control circuit to the motor. The motor runs in order to drive the lumbar up until the switch is released. When the lumbar switch is operated to move the lumbar down, battery positive voltage is applied through the lumbar down switch contacts and the driver seat lumbar down switch signal circuit to the massage module. In response to this signal, the massage module applies battery positive voltage through the driver seat lumbar down signal circuit to the MSM. The MSM then applies battery positive voltage through the seat lumbar motor down control circuit back to the massage module. The massage module, in turn, applies battery positive voltage through the lumbar motor down control circuit and ground through the lumbar motor up control circuit to the motor. The motor runs to drive the lumbar down until the switch is released. The MSM also controls the lumbar vertical motor through the massage module during memory recall operation.

POSITION SENSOR
The lumbar vertical position sensor is a potentiometer which is attached directly to the lumbar vertical motor it monitors. The MSM supplies a 5 volt reference voltage through the 5 volt reference circuit and ground through the low reference circuit to the lumbar vertical position sensor and the massage module. When the motor rotates, the resistance of the potentiometer varies changing the feed back voltage of the position sensor signal to the massage module. This voltage varies from 0.25 volts to 4.75 volts. During lumbar massage and non-massage operation, the sensor sends this voltage signal through the lumbar vertical position signal circuit to the massage module. During lumbar massage operation the massage module will output a simulated voltage signal through the lumbar vertical position signal circuit to the MSM. This simulated signal prevents the MSM from seeing the lumbar up/down motion and setting an erroneous diagnostic trouble code (DTC). After massage operation has ceased, the massage module will then update the MSM with the new feed back voltage value. The MSM monitors this feed back voltage to determine the position of the lumbar support for memory set and memory recall functions.

Memory Functions
Refer to Memory Seats Description and Operation.