Circuit Description
WARNING: This page is about a different car, the 2002 Oldsmobile Bravada, 2002 GMC Envoy XL, 2002 GMC Envoy, and 2002 Chevrolet TrailBlazer. However, it is still accessible from the selected car via links, so may be relevant.
The steering wheel controls are momentary contact switches that connect a series of resistors so that each switch selection corresponds to a fixed resistance value. The body control module (BCM) determines which switch has been pressed by the voltage drop across the corresponding resistance value. The BCM supplies voltage to the steering wheel controls through the rear wiper/washer switch supply voltage circuit. The BCM monitors the switch voltage on the remote radio control signal circuit.