Theory Of Operation
WARNING: This page is about a different car, the 2017 Jeep Cherokee. However, it is still accessible from the selected car via links, so may be relevant.
The Speed Control Switch uses a LIN Bus to communicate to the Steering Column Control Module (SCCM). The SCCM then broadcast the speed control switch status over the Can Bus. The Adaptive Cruise Control (ACC) module monitors the Can Bus for speed control switch status.