Theory Of Operation
WARNING: This page is about a different car, the 2014 RAM 3500 HD and 2014 RAM 2500 HD. However, it is still accessible from the selected car via links, so may be relevant.
The Body Control Module (BCM) receives a communication network message from the Steering Column Control Module (SCCM) requesting turn signal lamp illumination. When this bus message is received, the BCM provides a pulsed voltage output through the Rear Lighting Fault Sense circuit to the Turn Signal Lamps. A ground path for the Tail Lamps is provided through the wiring harness to the body sheet metal.