Theory Of Operation
WARNING: This page is about a different car, the 2013 RAM 3500 HD and 2013 RAM 2500 HD. However, it is still accessible from the selected car via links, so may be relevant.
When the Radio Frequency Hub (RF Hub) is awake, it sends a 12-volt reference signal on the T824 Transmission (TRS) Park Signal circuit. When that circuit is grounded or ungrounded by the shifter, transmission module or brake shift interlock solenoid (depending on the model) the RF-Hub broadcasts the hard wired park position message on the CAN Bus.