The 1968 Ford Mustang featured a single mechanically operated brake light switch mounted to the side of the brake pedal. As the pedal is depressed, a heavy spring in the center of the switch compresses. That compression activates a single wiring harness that plugs into the switch, which then illuminates the tail lights. A defective switch is typically caused by corroded electrical contacts. On occasion, the metal spring rusts and fails to trigger the electrical contacts. Fortunately, replacement brake switches are available for the 1968 Mustang, and installation is fairly straightforward.
Disconnect the wiring from the side of the switch. Note that each wire plugs into a single connector. Pull the connector off of the switch.
Crimp the two tips of the cotter pin together with pliers. The cotter pin is located next to the brake switch on the brake pedal assembly.
Pull the cotter pin out of the side of the brake pedal assembly with pliers to access the metal pushrod that protrudes through the firewall.
Slide the metal pushrod off of the brake pedal assembly to access a plastic washer.
Slide the plastic washer off of the side of the switch.
Slide the brake switch off of the brake pedal assembly.
Slide the new brake switch onto the brake pedal assembly.
Slide the plastic washer onto the side of the switch.
Slide the metal pushrod onto the brake pedal assembly.
Slide the cotter pin through its hole on the side of the brake pedal assembly.
Bend the two tips of the cotter pin apart with pliers to secure the switch and the metal pushrod in place.
Press the wiring connector onto the brake switch.
