Normal Operation
WARNING: This page is about a different car, the 2005 Mercury Mountaineer and 2005 Ford Explorer. However, it is still accessible from the selected car via links, so may be relevant.
The active brake booster has a normally open and a normally closed pedal force switch that operates according to driver brake applications.
The normally open pedal force switch circuit is 1581 (PK/LB). The normally closed pedal force switch circuit is 1580 (WH/LG).