Lumbar Support

Lumbar Support Description and Operation

Lumbar Support Components

The driver and front passenger pneumatic lumbar support system consists of the following components:

* Seat Lumbar support switch
* Seat lumbar adjuster valve assembly
* Seat lumbar support pump

Circuit Description

Battery voltage is supplied at all times to the driver and passenger seat lumbar support switches through 15 A fuses located in the underhood fuse block. When a lumbar switch is pressed to inflate the lumbar support, battery voltage is applied through the switch contacts and the inflate control circuit to the seat lumbar adjuster valve assembly. In response to this signal, the lumbar adjuster valve assembly energizes its internal inflate solenoid and applies battery voltage through the seat lumbar support pump control circuit to the pump. The pump runs to inflate the appropriate lumbar bladder until the switch is released. When the switch is pressed to deflate the lumbar support, battery voltage is applied through the switch contacts and the deflate signal circuit to the lumbar adjuster valve assembly. The lumbar adjuster valve assembly energizes its internal deflate solenoid and air is released from the bladder until the switch is released.

Description of Operation

The following describes the lumbar support operation and how the lumbar adjuster valve assembly responds to each of the lumbar support switch inputs:

* When the lumbar support switch pressed in the FORWARD direction, the lumbar adjuster valve assembly will command the lumbar support pump ON and the upper and lower lumbar support bladders should inflate until the bladders are 100% inflated or the switch is released.
* When pressing the lumbar support switch in the REARWARD direction, the lumbar adjuster valve assembly will slowly deflate the upper and lower lumbar support bladders until the switch is released or both bladders are 100% deflated.
* When the lumbar support switch is pressed in the UP direction, the lumbar adjuster valve assembly will slowly inflate the upper lumbar support bladder until the switch is released or the bladder is 100% inflated.
* When the lumbar support switch is pressed in the DOWN direction, the lumbar adjuster valve assembly will slowly deflate the upper lumbar bladder while it inflates the lower lumbar bladder. The lumbar adjuster valve assembly will continue this operation until the switch is released or the upper lumbar bladder is 100% deflated and the lower lumbar bladder is 100% inflated.