Brake On-Off (BOO) Switch
WARNING: This page is about a different car, the 1995 Ford RV Cutaway, 1995 Ford Econoline, 1995 Ford Cutaway, and 1995 Ford Club Wagon. However, it is still accessible from the selected car via links, so may be relevant.
BOO switch is wired to brakelight circuit. It signals the PCM when the brake is applied. The BOO input is used primarily by the torque converter clutch lock/unlock strategy.