Brake Pressure Applied (BPA) Switch
WARNING: This page does not describe the selected car, but rather 9 other vehicles, including the 2005 Ford RV Cutaway, 2005 Ford Pickup, 2005 Ford F550 Super Duty, 2005 Ford F450 Super Duty, and 2005 Ford Excursion. However, it is still accessible from the selected car via links, so may be relevant.
NOTE:
The BPA switch is present on vehicles equipped with speed control.
All vehicles have a single BPA switch. A BPA switch provides a backup for the brake pedal position (BPP) switch. Normally, a brakes-applied signal from the BPP switch disengages the speed control. If the BPP switch signal is lost, the BPA switch then supplies the brakes-applied signal to the speed control system. The BPA switch signal is also used in the transmission strategy and the key on engine running (KOER) self-test.