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) provides a battery voltage output to certain lamps through the courtesy lamp circuit. These lamps use a dedicated path to ground for illumination. The same lamp may also use a reading lamp circuit, which uses a switched path to ground for illumination. For additional information on the operation of the Courtesy Lamps. Refer to OPERATION .