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 for a specific voltage drop unique to the switch pressed. The radio identifies the switch selected and activates the feature or sends a serial data message to the component responsible for activating the feature.

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