Theory Of Operation
WARNING: This page is about a different car, the 2017 RAM 2500 HD. However, it is still accessible from the selected car via links, so may be relevant.
The Body Control Module (BCM) receives an input voltage from the headlamp switch. The BCM monitors the headlamp switch voltage and controls the exterior lighting functions based on the switch input. For additional information on Headlamp Switch operation. Refer to SWITCH, HEADLAMP, OPERATION .