The Ford brake pressure switch screws into the side of the brake master cylinder and tells the power train control module when you are applying the brakes. The most common cause of brake pressure switch failure is a fluid leak, where the switch meets the master cylinder. If left unchecked, the fluid then gets into the switch and shorts it out. When this happens to your Ford, you'll need to install a new Ford brake pressure switch to return your brake system to proper working order.
Open the Ford's hood and support it with the prop rod, unless the Ford has hood struts.
Disconnect the brake pressure switch from the brake wiring harness by hand.
Unbolt the brake pressure switch from the master cylinder with the 15mm box wrench.
Thread the new brake pressure switch into the master cylinder by hand. Tighten it with the box wrench until the switch is flush with the mount on the master cylinder.
Plug the new brake pressure switch into the brake wiring harness by hand. Close the hood.
