Theory Of Operation
WARNING: This page is about a different car, the 2010 Dodge Charger and 2010 Chrysler 300. However, it is still accessible from the selected car via links, so may be relevant.
The Steering Wheel Control Up Switch, when pressed, sends a multiplexed signal to the Right Steering Switch. The switching status is transferred to the Steering Column Control Module (SCCM) by way of the LIN bus, a serial sub-bus. The SCCM converts the data to CAN(B) and sends the message to the corresponding module on the bus.