A51 Lumbar Support System Operation
WARNING: This page does not describe the selected car, but rather 6 other vehicles, including the 2004 Oldsmobile Bravada, 2004 GMC Envoy XUV, 2004 GMC Envoy XL, 2004 GMC Envoy, and 2004 Chevrolet TrailBlazer. However, it is still accessible from the selected car via links, so may be relevant.
Battery voltage is supplied to the lumbar switch through the power seat 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 lumbar 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.