The Ford Focus' standard brake lights are owner replaceable. The lights are held within the brake light case on the rear of the car. This case also stores the turn signal and reverse light. The Ford Focus also has a third brake light, which is also known as a centre-high mounted brake light. This light uses LED bulbs and is designed to last the lifetime of the vehicle, according to the Focus' owner's manual. If the LED brake light stops working, visit an authorised Ford service centre.
Turn the exterior lighting switch next to the steering wheel off. Open the Focus' boot.
Remove the two plastic Phillips screws from the boot compartment. There are two screws on each side, one set for each brake light case. Pull the access cover off. You'll now see the case's hardware.
Remove the two case nuts with a socket wrench. Grasp the exterior part of the brake light case and pull it away from the Focus' rear.
Turn the brake bulb counterclockwise to detach it. The brake bulb is the middle bulb in the Focus' brake light case.
Grasp the bulb softly and pull it away from its socket. Insert the replacement brake bulb into the socket. Push it down gently to install it. Insert the set-up into its hole and twist it clockwise.
Set the brake light case in its mount. In the boot compartment, reattach and tighten the two nuts. Push the cover back in its place and replace the two plastic Phillips screws.