Brake Pressure Transducer
WARNING: This page is about a different car, the 2013 Ford F-550 Super Duty, 2013 Ford F-450 Super Duty, 2013 Ford F-350 Super Duty, and 2013 Ford F-250 Super Duty. However, it is still accessible from the selected car via links, so may be relevant.
The brake pressure transducer (if equipped) is mounted on the bottom of the master cylinder near the rear and sends a variable voltage to the ABS module depending on the pressure applied to the brake pedal. The ABS module receives this information directly from the pressure transducer.