The audio steering wheel control switches duplicate the function of the primary controls of the associated component through a network of multiple momentary contact switches and a series of resistors. The radio supplies voltage to the switches and monitors the return signal. When any switch is pressed, a specific voltage drops across the resistor. The radio identifies the option selected and activates the feature.

For steering wheel control switches not equipped with RPO K59, the body control module (BCM) supplies voltage to the Mute/Seek switches and monitors the return signal. When any switch is pressed, a specific voltage drops across the resistor. The BCM identifies the option selected and sends a serial data message to the component controlled by the switch activating the feature.

This section is intended to diagnosis the circuits between the radio or BCM and the steering wheel control switches. If the primary control for the device is inoperative, refer to the appropriate section for the component the steering wheel control switch controls.