Brake Pedal Position (BPP) Switch
WARNING: This page is about a different car, the 2004 Ford Pickup, 2004 Ford F550 Super Duty, 2004 Ford F450 Super Duty, 2004 Ford Excursion, and 2004 Ford Cab & Chassis. However, it is still accessible from the selected car via links, so may be relevant.
Brake status comes from brake pedal position (BPP) switch. The BPP sensor supplies battery voltage to the powertrain control module (PCM) that the brake pedal is applied. The PCM uses this input to disengage the converter clutch, speed control, and auxiliary idle (if equipped).