The 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 instrument panel module (IPM) supplies voltage to the switches and monitors the return signal for a specific voltage drop to occur unique to the one pressed. The IPM identifies the selection, then sends a serial data message to the component controlled by the switch and activates the feature.

This section is intended to diagnose the circuits between the IPM 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.