Theory Of Operation - Radio Remote Steering Wheel Switches

The switches in the two remote radio switch units are normally open, resistor multiplexed momentary switches that are hard wired to the left steering wheel switch. When the left steering wheel switch senses an input (voltage drop) from any one of the remote radio switches, it communicates the switch status message to the Body Control Module (BCM) via the LIN Bus (through the clockspring). The BCM broadcasts switch status information over the CAN bus to the audio system. Electronic circuitry within the audio system is programmed to respond to these remote radio status messages by adjusting the audio settings as requested.