How to Guides

How to Replace a Broken Tail Light

Zaki Moulvi posted this on May 30, 2014

The tail light assembly on your car is critically important to your safety, and yet one of those car parts that you don’t realize isn’t working right until it is too late.  Here lies the brake light to let drivers behind you know when you are slowing down or stopping.  There is also the turn signal to alert traffic behind you of your intent to change lanes or exit and the reverse light for when you are backing up.  In addition, they illuminate with your headlights when driving at night so that other vehicles are aware of your presence.

How Can You Tell They are Out

There are a few different variations of tail light assembly’s being used on cars today.  Some rely on a single bulb system, which means you lose it all if the bulb burns out, while others use multiple bulbs for the different functions.  You may get a warning light on your dash if a tail light has gone out.  For the turn signal lamp there are vehicles that will alert you to a burnt bulb by quickening the beat of the clicks when you signal to turn.  The only sure way to tell what is going on back there is to enlist the help of a buddy and have them stand at the back of the car while you run through all of the different tail light functions.  Note the ones that don’t engage and get to work changing them before you get a traffic ticket or worse.

Before You Get Started:

  • Check the fuse box for any blown fuses.  The tail light assembly is an electrical component that relies on a number of different fuses to work.
  • Your car will usually have two fuse boxes, one inside the engine and one in the cabin.  Both can contain fuses relevant to the tail light assembly.  If you are unsure consult the diagram that is next to it or your owner’s manual.
  • Once you find the fuses associated with your tail light assembly check to see that the filament is attached.  If it is broken than all you need to do is replace it with a matching fuse.  Be sure that the voltage and size that you replace it with is the same.
  • Blown fuses are often indicative of other, underlying electrical problems.  After changing the ones for your tail light assembly check how they are functioning for a few days afterwards.  If the fuse blows out again quickly, you will need to delve deeper to find the source of the problem.

All the Fuses are Fine

Once a blown fuse has been ruled out, it is time to look at the tail light assembly itself.  It can usually be accessed through the trunk of your car.


  • Take a look at the wiring leading to the tail light assembly.  Sometimes a harsh bump in the road can cause one to come loose.  If so, reattach and then check to see if that has resolved your tail light issue.
  • If the wiring is fine you will need to look at the bulbs.  You will need to unscrew the tail light cover to get to them.  If there are no screws on the tail light cover than the bulbs are probably easily accessible through the trunk.
  • When you take the bulb out you are going to examine it in the same way you do one in your house.  Hold it up and look at the filament, if it is broken then the bulb needs to be replaced.
  • If the bulb is not the issue and you are confident that the fuses and wiring were all in good shape then you have an electrical system issue with your car that needs to be addressed by a mechanic.

Important to Note:

  • The lens covers for your tail light assembly are very important for protecting the electrical components inside.  If you have one that is cracked or has a hole than water can be entering and damaging important parts.  Replace or repair a broken tail light cover to avoid future problems.
  • If you are having difficulties finding access to the bulbs inside the tail light assembly consult your owner’s manual.

It may not seem like much, but replacing your tail lights is not something that you should put off.  If you are still unsure on how to do it watch a pro in action and get some more helpful hints on how to make the job an easy one.

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