Lumbar Support

LUMBAR SUPPORT DESCRIPTION AND OPERATION

LUMBAR SUPPORT/TORSO BOLSTER SYSTEM COMPONENTS
The lumbar support/torso bolster system for the driver and passenger consists of the following components:
- Driver and passenger lumbar support/torso bolster switches
- Driver and passenger lumbar support/torso bolster motor assemblies
- Driver seat module
- Memory select switch
- Driver door module
- SEAT 30A circuit breaker

LUMBAR SUPPORT/TORSO BOLSTER SYSTEM OPERATION
The power lumbar support/torso bolster system is only available with the driver memory, 8 way power seats option. The driver seat lumbar and torso adjuster motors are controlled through the driver seat module, while the passenger seat lumbar and torso adjuster motors are controlled directly through the lumbar support/torso bolster adjuster switch.

The driver seat module supplies the driver seat lumbar support/torso bolster adjuster switch assembly with a battery positive reference voltage. While the switches are in an inactive state the switch contacts are closed to the switch ground circuit. When a switch is pressed to an active state the switch contact is closed to the reference voltage circuit. Battery voltage on a switch signal circuit indicates to the driver seat module the switch status is active. Each seat adjuster motor is controlled by the driver seat module through 2 motor control circuits. While the seat adjuster motors are in an inactive state the motor control circuits are closed to ground circuit contacts within the driver seat module. The driver seat module operates the seat adjuster motors by switching one of a motor's control circuits to battery voltage. The seat adjuster motors are bidirectional and the direction of adjuster motor rotation is determined by which of the adjuster motor control circuits is switched to battery voltage while the other remains grounded.

The seat adjuster motors are equipped with internal position sensors. The adjuster motor position sensors are monitored by the driver seat module and are used to determine the seat position when storing or recalling memory settings. The lumbar and torso adjuster motors use hall effect type position sensors. The hall effect position sensors are supplied with battery positive reference and ground circuits from the driver seat module. The position sensor signal circuits are supplied battery positive voltage through a resistor them monitored within the driver seat module. During adjuster motor operation the hall effect position sensor provides a single pulse for every revolution of the adjuster motor shaft. The driver seat module counts the pulses from the position sensor signal circuits to determine the adjuster motor positions when storing or recalling memory seat position settings.

Battery voltage is supplied to the passenger seat lumbar support/torso bolster switch through the SEAT 30A circuit breaker. While the switches are in an inactive state the switch contacts are closed to the switch ground circuit. When a switch is pressed to an active state the switch contact is closed to the battery voltage supply circuit. Each motor is controlled by the power seat switch through 2 motor control circuits. The motors are bidirectional and the direction of motor rotation is determined by which of the motor control circuits is switched to battery voltage while the other remains grounded.