Stop Lamp Switch - Operation

OPERATION

The brake (or stop) lamp switch controls independent circuits. These circuits are described as follows:

- Normally Closed - The normally closed circuit provides a hard wired output to the Body Control Module (BCM) indicating the position of the brake pedal, depressed or released. The BCM responds by relaying electronic brake switch status messages over the Controller Area Network (CAN) data bus to other electronic modules in the vehicle.
- Normally Open - The normally open circuit provides hard wired outputs to the BCM and the Powertrain Control Module (PCM) whenever the brake pedal is depressed. The BCM responds to the normally open input by providing a control output that energizes or deenergizes the brake lamps.

The brake lamp switch as well as the hard wired inputs and outputs of the switch may be diagnosed using conventional diagnostic tools and procedures. Refer to the appropriate wiring information. However, conventional diagnostic methods will not prove conclusive in the diagnosis of the electronic controls and communication that provide some features related to brake lamp switch operation. The most reliable, efficient and accurate means to diagnose the electronic controls and communication related to brake lamp switch operation requires the use of a diagnostic scan tool. Refer to the appropriate diagnostic information.