Theory Of Operation
WARNING: This page is about a different car, the 2008 Dodge Magnum, 2008 Dodge Charger, and 2008 Chrysler 300. However, it is still accessible from the selected car via links, so may be relevant.
The Steering Wheel Control Audio Switch, when pressed, sends a multiplexed signal to the Right Steering Switch. The switching status is transferred to the Steering Control Module (SCM) by way of the LIN bus, a serial sub-bus. The SCM converts the data to CAN(B) and sends the message to the corresponding module on the bus.