Lumbar Support System Operation
WARNING: This page is about a different car, the 2002 GMC Sierra, 2002 GMC Cab & Chassis Sierra, 2002 Chevrolet Silverado, and 2002 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.
The lumbar support and bolster motors are operated by a four position switch in each seat. Battery voltage is supplied to the lumbar/bolster switch from the SEAT 25A circuit breaker. While the lumbar/bolster switches are in an inactive state the switch contacts are closed to the lumbar/bolster switch ground circuit. When a lumbar/bolster switch is pressed to an active state the switch contact is closed to the battery voltage supply circuit. Each lumbar/bolster motor is controlled by the lumbar/bolster switch through 2 motor control circuits. The lumbar/bolster 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.