Hobbies Cars & Motorcycles 2005-2009 Ford Mustang: Replacing a Brake Light Share PINTEREST Email Print Sicnag/Flickr/CC BY 2.0 Cars & Motorcycles Cars Mustangs Basics How Tos Reviews Classic Cars Corvettes Tires & Wheels Motorcycles Used Cars Trucks ATVs & Off Road Public Transportation By Jonathan Lamas Jonathan Lamas Jonathan Lamas is a seasoned automotive journalist. He has covered cars and the auto industry for Forbes Autos, Car and Driver, Consumer Guide, and other outlets. Learn about our Editorial Process Updated on 02/23/19 Sooner or later, you’re going to have to replace a brake light on your Ford Mustang. How do you know when it’s time to complete this task? Well, a telltale sign is a turn signal that chimes faster than usual when you make a turn. If this happens when you put your left turn signal on, a bulb on the left side of the vehicle has likely gone out. Either that, or it’s loose. If it happens when you use the right turn signal, it’s likely a bulb on the right side of the vehicle needs replacing. Years ago, replacing a bulb was pretty simple. Owners of 2005-2009 Mustangs will find this task is a bit more involved than in the old days, as it requires removing some trunk trim and a few retaining screws. The entire tail light assembly must then be carefully removed to gain access to the bulb sockets in the rear. What follows is a step-by-step replacement of a brake light on a 2008 Ford Mustang. For information regarding other model years, please consult your owner's manual or contact your local Ford Dealer. To do this, you'll need the following: Small flathead screwdriver1/4-inch drive 7/16 or 11mm socket and ratchetSylvania 4057 or 4057LL replacement bulb The total time required is about 15 minutes. 01 of 14 A Burned-Out Bulb Jonathan P. Lamas As you can see, one of the two brake light bulbs on this Mustang (in the center) is not working. 02 of 14 Clean out the Trunk Jonathan P. Lamas Make sure your trunk is empty. 03 of 14 Remove the Trim Screws Jonathan P. Lamas Remove the plastic screws from the left and right side trunk trim. 04 of 14 Remove the Center Pin Lock Retainers Jonathan P. Lamas Remove the four center pin lock retainers from the trim panel. Using a flathead screwdriver or your finger, lift up the center of the pin. You can then remove the rest of the pin. Caution: Don't use too much force because the retainers could break. 05 of 14 Remove the Plastic Trunk Trim Piece Jonathan P. Lamas Now that the trim screws and center pin lock retainers have been removed, you can carefully remove the plastic trunk trim piece by lifting it up and out of the trunk. 06 of 14 Remove the Nuts Jonathan P. Lamas Now it’s time to remove the three 11mm nuts on the back of the light. Because we are replacing the brake light on the right side of the vehicle, we’ll focus on the right light. Tip: Keep track of each nut and pin so they don’t get lost. 07 of 14 Put Down Protective Cloth Jonathan P. Lamas After removing the nuts, tilt the light assembly forward so you can access the bulb compartments. Before doing so, make sure to put a protective cloth underneath the assembly to protect the bumper from scratches. 08 of 14 Remove the Old Bulb Jonathan P. Lamas Because you previously noted which light had burned out, you can now remove that light by tilting the entire taillight assembly forward and twisting the old bulb out of its socket. 09 of 14 Install the New Bulb Jonathan P. Lamas Now you can replace the burned out bulb with a new bulb. Although Ford recommends using Sylvania 4057 or 4057LL, several people have reported success when using the Sylvania 3157LL bulb, which happens to be more readily accessible at local retail stores. As always, consult your owner’s manual or local Ford dealer for advice regarding the correct part. 10 of 14 Test the New Bulb Jonathan P. Lamas Before you put everything back together, make sure the new bulb is functioning properly. As you can see here, both brake lights function. Problem solved. Now it’s time to put everything back together. 11 of 14 Reposition the Taillight Assembly Jonathan P. Lamas Carefully place the taillight assembly back into its correct position, making sure it's seated snug and tight. Reinstall the three nuts at the rear of the assembly. Be extra careful not to drop the taillight assembly during this step. 12 of 14 Replace the Trunk Trim Jonathan P. Lamas With all three nuts back in place, carefully replace the trunk trim back into the trunk. 13 of 14 Replace the Center Pin Lock Retainers Jonathan P. Lamas Replace the four center pin lock retainers by pushing them firmly into position. 14 of 14 Replace the Trim Screws Jonathan P. Lamas Now replace the two trim screws by turning them to the right. After they're in place, double check to make sure the trim is tight and properly seated. Congratulations: you have now successfully replaced your brake light. Note: If you notice a loose nut or a piece of trim that's out of place, go back through the above steps until everything is back together.