Lumbar Support

LUMBAR SUPPORT DESCRIPTION AND OPERATION

The driver and passenger lumbar support systems each consist of the following components:
- Upper lumbar switch
- Lower lumbar switch
- Lumbar pump/control module
- Upper lumbar support bladder
- Lower lumbar support bladder
- POWER LUMBAR LH/RH Fuse 15 A

Power and Ground
Battery positive voltage is supplied at all times to the driver and passenger lumbar support switches and the lumbar pump/control modules through the battery positive voltage circuit and the POWER LUMBAR LH/RH Fuse located in the instrument panel (I/P) fuse block. Ground is provided through the module ground circuit to the ground stake.

Lumbar Support System Operation
This is a power inflate/deflate pneumatic system used for controlling seat back comfort by inflating or deflating air bladders within the seat back cushion.

The upper and lower lumbar support in the seat backrest may be adjusted independently. When the upper lumbar switch is operated to inflate or increase the amount of lumbar support, battery positive is applied through the switch contacts and the upper lumbar inflate control circuit to the lumbar control module. In response to this signal, the lumbar module energizes its internal inflate relay and the pump motor runs to inflate the upper lumbar support bladder in the seat backrest until the switch is released. When the upper lumbar switch is operated to deflate or decrease the amount of lumbar support, battery positive voltage is applied through the switch contacts and the upper lumbar deflate control circuit to the lumbar module. In response to this signal, the lumbar module releases air from the upper lumbar support bladder until the switch is released. The lumbar lower support is also controlled this way.