Theory Of Operation
WARNING: This page is about a different car, the 2015 RAM 3500 HD and 2015 RAM 2500 HD. However, it is still accessible from the selected car via links, so may be relevant.
The Body Control Module (BCM) monitors the hardwired ignition switch input circuit from the Radio Frequency (RF) Hub module and compares it to the ignition switch status message received over the Controller Area Network (CAN) bus.