Theory Of Operation
WARNING: This page is about a different car, the 2020 Jeep Renegade. However, it is still accessible from the selected car via links, so may be relevant.
The Body Control Module (BCM) monitors the inputs from the Stop Lamp Switch. The Stop Lamp Switch contains a normally open switch and a normally closed switch. Separate fused ignition run/start voltage circuits supply voltage to the switches. When the BCM detects the brakes are applied, the BCM sends a voltage output to the Left and Right Tail Lamp Assemblies and Centered High Mounted Stop Lamp. A ground path for the lamps is present through the harness to the body sheet metal.