Circuit/System Description
WARNING: This page is about a different car, the 2016 Cadillac CTS. However, it is still accessible from the selected car via links, so may be relevant.
The Steering Wheel Controls are divided into a right-hand set and left-hand set. The right-hand switch is connected to the IPC LIN serial data and provides input from the left-hand switches. The IPC identifies the switch selection and activates the feature.