Theory Of Operation
WARNING: This page is about a different car, the 2015 Fiat 500. However, it is still accessible from the selected car via links, so may be relevant.
The Body Control Module (BCM) receives a hardwired brake signal from the Stop Lamp Switch indicating that the Brake Pedal is applied. When this signal is received, the BCM provides a voltage output through the rear stop signal control circuit. For additional information on the Brake Lamp operation. Refer to BRAKE LAMPS .