Troubleshooting tail lights can be done alone or with an assistant. For obvious reasons, the lights must be working properly. In some states, there are stiff fines and "fix it" tickets issued for blown tail lights. If you suspect that you may be having problems with your lights, you can easily troubleshoot the problem before replacing anything.
Step on the brake pedal and have an assistant check to make sure that the tail lights are working properly. If they are not, check the bulb, the wiring, and the fuse.
Open the fuse box panel, usually located underneath the steering wheel. Pull out the fuse for the tail lights with a fuse puller (on the fuse panel lid), and check to make sure that the fuse is not popped. Put it back if it is not blown. If it is, you'll need to replace it.
Open the trunk or rear hatch area. Remove any panels covering the rear tail light assembly. Some vehicles use simple removable trim pieces that snap in and out of place, while others use retaining screws or wing nuts to secure a trim piece to the back of the tail light housing. You also may need to pull up the trunk carpet to gain access to the rear tail lights.
Remove the electrical plug running to the tail lights. Squeeze the release tab on the top of the plug and pull the electrical connection apart.
Turn the bulb counterclockwise to unlock it from the housing and remove it by pulling it straight out of the housing. Inspect the bulb's filament. If the filament is broken, replace the bulb with a new one.
Check the wiring running to the tail light housing. If there is a short or damage, it is mostly likely where the wiring is exposed-at the tail light housing. Check for any damage. If the wiring is damaged, it will have to be checked and serviced by a professional mechanic.
