Steering Wheel Controls
WARNING: This page is about a different car, the 2007 Chevrolet Corvette. However, it is still accessible from the selected car via links, so may be relevant.
Some audio functions are available using the steering wheel controls. The steering wheel controls consist of multiple momentary contact switches that connect a series of resistors. When a steering wheel control button is pressed, a specific resistance value is noted by the dash integration module (DIM). This results in a generated voltage, unique to the particular button. The DIM alerts the radio that the button has been pressed, and the radio responds, just as if the corresponding radio front panel button had been pressed.