The third brake light on a vehicle is mounted either in the rear window on a car or on the top of the roof on a truck or SUV. This is designed as a dedicated brake light mounted high on the vehicle, giving people behind the vehicle a good indicator of when the vehicle is stopping. You may need to remove this light if the bulb is out or if the brake light needs to be replaced. In this case, the project vehicle is a 2009 Chevrolet Silverado, but the process is similar for other vehicles as well.
Climb into the back of the truck and position yourself so that you can access the third brake light. Remove the screws securing the brake light in place with the Phillips screwdriver.
Pull the third brake light off of the roof with your hands. Unplug the wiring harness to the brake light assembly and take the third brake light away from the vehicle.
Unscrew the bulb mounting panel from the back of the third brake light assembly using the Phillips screwdriver. Pull the bulbs out and away from the housing.