Tail lights often fail for a variety of reasons. The Bulb itself may have burned out, there may be a faulty line or a disconnection, and the tail light needs to be replaced.
Remove the old tail light bulb
Open the trunk or Tailgate of the vehicle, release the button from the driver side of the vehicle to eject it or pull the handle on the tailgate to lower it so that you can touch the back of the tail light assembly.
Remove the fabric pad or panel that covers the back of the tail light. Do not remove the fabric completely so that it can be placed back under the trim when finished. If your vehicle does not allow you to touch the fabric lining or panels on the back of the tail light, use a screwdriver to remove the screws or a wrench to remove the bolts and gently slide the entire lamp assembly out to avoid disconnecting the wires to the back of the tail light.
Find the socket that holds the burned bulb in place and grab the back of it. Turn the socket to the left and pull it out from the back of the lamp. Press the bulb in the socket and slide it out. Some light bulbs may require you to unscrew them to get them out of the socket.
Install a new tail light bulb
Wear a pair of nitrile gloves to prevent damage to the light bulb. Slide a new version of the same type of light bulb into the socket. Choose a replacement bulb that is the same size and wattage as the old bulb. Replace the socket and turn it to the right to secure the bulb, gently swinging the socket to ensure that it is securely fastened to the assembly.
Place the fabric lining or panel back on the back of the Lens. If you come into contact with the rear of the tail light through the trunk or Tailgate, cover the rear of the tail light assembly with a fabric lining that you pull back, or reinstall the removed plastic panel. If your panels have brackets to hold them in place, align them with the connections on the vehicle and push the panels until you hear them snap into place.
If you have removed the lamp assembly or LID and Fastener, reinstall them. Close the trunk or Tailgate and start the vehicle to test the bulb. If you install the bulb correctly and it still doesn’t work, it could be a fuse or an electrical problem that needs to be checked by a licensed mechanic.