Michael Aguilar

Installing a Third Brake Light/Collision Avoidance Brake Light Lead.jpg All images by author with help from friends except where otherwise noted. United States law has mandated for a number of years that all vehicles sold in the United States be equipped with a brake light at the eye level of drivers following behind. These are called either third brake lights or collision avoidance lights. These lights weren’t normally factory-installed on vehicles prior to the 90s. Most insurance companies will give a healthy discount on your premiums if you install a third brake light on your older car. Advance Auto Parts is going to show you how to install one quickly and easily. -_sdr_-_pri_larg.jpg Spyder Auto Center high Mount Stop Light-LED, Clear Lens, Red Bulb Advance Auto Parts VEHICLE SYSTEM Electrical SKILL LEVEL Learner A knowledge of basic hand tools is all that’s (usually) required for this project. Time To Complete This is a job that can be completed in about an hour. -_sdr_-_pri_larg.jpg Spyder Auto Center High Mount Stop Light-LED, Clear Lens, Red Bulb Advance Auto Parts WHAT YOU’LL NEED Ratchet and sockets Wrenches Side cutters/wire cutters Screwdrivers Crimpers Test light or multimeter New third brake light kit Cable ties -_gro_54002_pri_larg.jpg Grote SuperNova® Turtleback ® II LED High Mount Stop Turn Marker Light, Red Advance Auto Parts 1 Attaching.jpg Determine where you’re going to mount the third brake light. It needs to be centered and above the line of the vehicle’s normal brake lights. This will probably require drilling and sealing on trucks, wagons, utility vehicles, and vans. The light can be mounted on the rear package tray of sedans and coupes with two self-drilling screws. The edge of the trunk lid, rear door, or cab are all possible locations also. The image above shows the light assembly being attached the station wagon’s rear window with double-sided tape included with the kit. Access.jpg You may have to remove plastic trim panels from the vehicle interior and/or carpeting in the trunk to mount the new light and route its wiring. These were usually secured in older vehicles with a few Phillips screws and some fragile plastic push clips. Although there are special tools available to lessen your chances of breaking these clips, being careful and only applying enough pulling pressure (at a perfect 90 degree angle) to the clip and trim panel, most will come out without breaking. Advance also carries a full stock of these if you do break any or find any already broken (Quite likely on older vehicles.). As shown in the image above you may also be able to tuck the third brake light wiring behind the rubber gasket on the rear window. 2 Remove Assembly.jpg Gain access to the wiring of both passenger- and driver-side brake light assemblies. This will normally require removing the lenses or the housings with a Phillips screwdriver on wagons, trucks, and vans. You can get at them on most coupes and sedans through the trunk without removing the light assemblies. 3 Brake Light.jpg Locate the pigtails/sockets for the brake lights and have someone step on the brake or use a stick or rod to lock the brake pedal down enough to light the brake lights. Don’t turn any other lights on. Mark the wires and allow the brake pedal to return and turn off the brake lights. 4 Probing.jpg Probe the wires on the backs of the sockets with the test light or meter until you find the leads with power. Check the kit’s instruction to see if you have to connect the third brake light (or high mount brake light) to both stop lights so it doesn’t flash with the turn signals. 5 Routing.jpg Route the third brake light wires to the passenger- and driver-side stop light pigtails. 6 Splices.jpg Use wire crimpers to connect the included splices to the third brake light wires to the vehicle’s brake light wires. Most kits will come with inline taps. The vehicle wires are inserted first in the through hole, followed by the wires from the kit until the stop. Squeeze the jumper connector down until flush with pliers and close and latch the cover. If the kit comes with butt connectors, cut the vehicle wires and strip back ¼ inch of the insulation on all three wire. Twist the vehicle wire and the kit wire together and insert them in one end of the butt connector. Twist and insert the pigtail wire into the butt connector and firmly crimp the connection. Tug on the wires to make sure you have a good crimp. PRO TIP Don’t scrimp on low quality/cheap crimpers. They don’t make solid crimps that won’t come apart and/or break over time. 7 Ground.jpg Run the ground wire from the third brake light kit to a solid body or chassis ground location. If you can find an existing location where this is an OEM ground, use it. Clean the screw/bolt and top ground connector to ensure a solid ground connection. If you have to use a new hole for the ground, be sure to remove the paint around it to get a good ground. 8 Test.jpg Test your work. Get someone to step on the brakes and make sure the original brake lights still work and that the new third brake light/collision avoidance light/high mount brake light all come on. Next, test the hazards/flashers. If the brake lights are also the turn signals, the new brake light should flash with the hazards, but not with the turn signals. Now, turn on the headlights to make sure the tail lights don’t also light up the new brake light. 9 Cleanup.jpg Clean up your wiring. Use small wire/cable ties every foot or so to integrate the new wires into the existing harness and to secure them up to where they enter the new light assembly. For an even cleaner look you can wrap the wires and vehicle harness in OEM-style cloth tape, or for even better protection you use split-loom plastic conduit. You can get even fancier and secure the wires to the body with plastic or rubber coated wire clamps and self-drilling screws. This gives you a cleaner and more professional installation and keeps the wires from moving around and being pinched by moving parts or squashed by cargo in the trunk area. 10 Reassembly.jpg Replace the light assemblies and trim panels you took off during the first steps of this project. Although the reasoning (Looks over safety/lower insurance premiums) and the mounting locations are different, these steps can also be used to install brake lights in trailer hitches, camper tops, and under rear spoilers/diffuser on newer cars to look like those on F1 and rally cars. Advance Auto Parts also carries a full line of accessory wire and connectors if you need to extend the wires from the third brake light kit to reach the vehicle’s wiring.