Circuit Description
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.
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.