How to Install an Aftermarket Tail Light

Installing aftermarket tail lights is relatively straightforward as custom car modifications go. Make sure that you purchase the correct tail light assemblies for your make and model vehicle. If the lenses or bulbs don't fit, it can turn a pretty simple job into an afternoon of frustration, and an extra trip to the auto parts store.

Getting Started

Disconnect the negative battery terminal, eliminating any risk of shock. Next, open your trunk and look around the back wall for ways to remove the interior paneling for access to the back of the tail light assemblies. Depending on your vehicle, this could be as simple as a plastic latch, or at most it could involve a few screws. Your owner’s manual will most likely give you instructions for gaining access to the tail lights.

Remove Original Bulbs and Lenses

Once you have access to the backside of the tail lights, remove the bulbs by pulling the socket and wire bundle out of the housing. This is often accomplished with either an unscrewing motion, or some sort of pinch-clip. Move the bulb and associated wires out of the way to avoid damaging them. Don’t install your new bulb or LED assembly until everything else is finished; you don't want to risk damaging the new parts while finishing the replacement of the old.

To remove the existing lenses, there will often be screws either on the interior or, in rare cases, the exterior of the lens housing. Remove any screws, bolts, or clips you find, making sure to save them and note their original location. Most likely, you will use the same screws to fasten your new assembly, unless it came with its own hardware (and even then it's a good idea to keep the old, in case the new fasteners don't fit).

Installing the New Tail Lights

Fit the new tail light housing where you removed the original. This is the moment of truth—if you accidentally picked up the wrong assembly, you’ll know it. The new housing should slip right in, and should match up perfectly with the screws, bolts, or clamps that held the original housing in place. Attach it as firmly as possible without over-tightening the screws or bolts (screwing them in too tightly can crack the tail light housing or strip the threads that receive the screw).

Finally, remove the old bulbs from the light assembly that you pulled out of the housing early in the installation. Check your owner’s manual if you have problems, but the bulbs are often removed by pushing in and turning counter-clockwise a half or quarter turn. If the bulbs are still working, it’s a good idea to set them aside as backups in case your new lights go out. Insert the new bulbs as you removed the old ones, and replace the light assembly within the housing, again doing the reverse of what you did to remove them at the beginning. Replace the panels in the trunk, if there were any, and your installation is almost complete!

Test and Go!

The last step before you’re ready to hit the streets is to make sure your tail lights are working. Police can and will ticket for non-working tail lights, so it’s best to check them beforehand. Reattach your battery, turn on your headlights, and make sure everything’s working. To make absolutely sure everything is working, have a friend watch the lights while you hit the brakes as well. If the lights are working, you’re ready to go!