Lumbar Support (Without Memory A45)

Lumbar Support Description and Operation (Without Memory A45)

Lumbar Support Components

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

* Seat adjuster switch

* Seat lumbar support module

* Seat upper lumbar motor

* Seat lower lumbar motor

Lumbar Description of Operation

The lumbar support is a dual zone mechanical lumbar system that is designed to move the lumbar support either forward, rearward, up, or down. The system has 2 motors and a lumbar control module that is used to direct power to the motors to accomplish the following functions:

* When the lumbar forward switch is pressed, both lumbar motors are activated to move the upper and lower lumbar support forward.

* When the lumbar rearward switch is pressed, both lumbar motors are activated to move the upper and lower lumbar support rearward.

* When the lumbar up switch is pressed, the upper lumbar motor is activated to move the upper lumbar forward while the lower lumbar motor is activated to move the lower lumbar rearward.

* When the lumbar down switch is pressed, the lower lumbar motor is activated to move the lower lumbar support forward while the upper lumbar motor is activated to move the upper lumbar support rearward.

Circuit Description

Battery voltage is supplied at all times to the driver and passenger seat adjuster switches through 15 A fuses located in the underhood fuse block. Ground for each adjuster switch is supplied through the switch ground circuit and ground connection. Battery voltage is always applied on the input of the indicated direction. Lumbar motor power and ground distribution is accomplished by the lumbar support module as described below:

* Lumbar Forward/Rearward - When the lumbar forward switch is pressed, battery voltage is applied through the switch contacts and the lumbar forward control circuit to the lumbar support module. The voltage is then directed through the module and the lumbar forward control circuits to both the upper and lower lumbar motors. With the lumbar support rearward switch contacts always closed to ground, both motors run to drive the lumbar support forward towards the occupant's back until the switch is released. Moving the lumbar support rearward works similarly to moving the lumbar support forward, except that battery voltage and ground are applied on opposite circuits causing the motors to run in the opposite direction.

* Lumbar Up - When the lumbar up switch is pressed, battery voltage is applied through the switch contacts and the lumbar up control circuit to the lumbar support module. The module directs this voltage through the upper lumbar forward control circuit and the lower lumbar rearward control circuit to the lumbar motors. At the same time the module directs ground through the upper lumbar rearward control circuit and the lower lumbar forward control circuit to the lumbar motors. The upper lumbar motor runs to drive the upper lumbar support forward towards the occupant's back while the lower lumbar support motor runs to remove lower lumbar support away from the occupant's back.

* Lumbar Down - When the lumbar down switch is pressed, battery voltage is applied through the switch contacts and the lumbar down control circuit to the lumbar support module. The lumbar support module directs this voltage through the lower lumbar forward control circuit and the upper lumbar rearward control circuit to the lumbar motors. At the same time the module directs ground through the lower lumbar rearward control circuit and the upper lumbar forward control circuit to the lumbar motors. The lower lumbar motor runs to drive the lower lumbar support forward towards the occupant's back while the upper lumbar support motor runs to remove upper lumbar support away from the occupant's back.