Brake Pedal Switch (BPS)/Brake Deactivator Switch
WARNING: This page does not describe the selected car, but rather 32 other vehicles, including the 2005 Mercury Sable, 2005 Mercury Mountaineer, 2005 Mercury Monterey, 2005 Mercury Montego, and 2005 Mercury Mariner. However, it is still accessible from the selected car via links, so may be relevant.
The BPS, also sometimes called the brake deactivator switch, is for vehicle speed control deactivation. A normally closed switch supplies battery positive voltage (B+) to the PCM when the brake pedal is NOT applied. When the brake pedal is applied, the normally closed switch opens and power is removed from the PCM.
On some applications the normally closed BPS, along with the normally open brake pedal position (BPP) switch, are used for a brake rationality test within the PCM. The PCM misfire monitor profile learn function can be disable if a brake switch failure occurs. If one or both brake pedal inputs to the PCM did not change states when they were expected to, a diagnostic trouble code P1572 can be set by the PCM strategy.