When you open the trunk at night and the only thing you see is a black hole you’ll probably wish you knew how to change a trunk light bulb.
If the trunk light doesn’t work you can’t see where to put your things when it’s dark. Even worse, you’ll have a hard time finding the spare wheel and jack if you get a flat tire at night.
These should be good enough reasons to learn this. Also, the repair isn’t time-consuming and you won’t need lots of tools.
If you’re not in the mood for reading, you can watch a YouTube video tutorial at the end of the article or on our YouTube channel.
WHAT WILL YOU NEED TO CHANGE A TRUNK LIGHT BULB?
As mentioned, this repair isn’t needy in terms of tools.
You’ll need (in most cases):
- Small flathead screwdriver or plastic trim tool
The screwdriver is for taking out the plastic trunk light housing (the place where the light bulb is located). A plastic trim tool would be better as there is less chance of scratching or damaging the surrounding trim panel or the housing.
- Spare light bulb
The usual trunk light bulb is a 12 volt,5 watts one. It will probably be a C5W or W5W (in most cases).
Best check what’s the exact one on your car before you start.
One more good thing to do is confirm that the bulb is the actual problem. Best use either a multimeter or tester to confirm that. If there’s electric input to contacts holding the bulb, then the bulb is surely the problem.
If there isn’t, then changing the bulb will not solve the problem.
Of course, one more way is checking the bulb visually. If the filament is burnt out or the glass balloon is foggy and black, then the bulb is likely the problem.
HOW TO CHANGE A TRUNK LIGHT BULB?
1. LOCATE THE TRUNK LIGHT
Obviously, the first thing you should do in order to learn how to change a trunk light bulb is to find the light housing.
For readers who have no experience in car repairs, look around the trunk for a small plastic, glassy-looking rectangle. Usual locations are on either side of the trim panels or in the upper part of the trunk, under the rear windshield.
On most cars, there is only one light but there may be more.
2. REMOVE THE TRUNK LIGHT HOUSING
In most cases, the light housing will be held in place with a clip system. This means the housing is meant to be pulled out and pressed back in.
To take it out, first, find a small opening around the outer edge of the housing. Here, you’ll insert either the screwdriver or trim tool.
Slowly raise the housing until one side comes out completely. After this, easily pull out the other side. Don’t use too much force so you don’t damage the housing or the wiring attached to it.
From this point, you can change the light bulb either while the housing is connected or disconnect it completely from the wiring installation.
The first option is faster but the other one is safer. When you disconnect the housing, there’s no danger of a short circuit. Leaving it connected is a good option if the connector is stubborn and won’t come off. This way you’ll avoid damaging it thus causing more problems.
3. REPLACE THE OLD LIGHT BULB
Pull the old bulb out.
In some cases, you might need a pair of pliers if the contacts holding the bulb are a bit stiffer.
In case you have to pick out the bulb while the housing is connected to the wiring, use a small wooden stick (not a metal one).
This way you’ll avoid accidentally causing a short circuit and blowing a fuse.
When inserting the new bulb, make sure it sits in place properly and has good contact.
4. CHECK THAT THE LIGHT WORKS
The bulb will start to shine immediately after replacement if the trunk is open and the housing is connected.
Remember that the light works only when the trunk is open.
On the other hand, if you’ve disconnected the housing, the bulb will work right after reconnecting it.
If the trunk light doesn’t work after the bulb replacement, check the list below for other possible reasons for the problem.
5. RETURN THE TRUNK LIGHT HOUSING BACK INTO PLACE
For the final step in learning how to replace a trunk light bulb, return the housing back into place.
First tuck in the wires and connector. Then align the light housing with the opening on the trim panel and push in until you hear a click sound.
Again, don’t hurry or use too much force so you don’t damage the plastic housing or trim panel.
OTHER REASONS FOR A BAD TRUNK LIGHT
If changing the light bulb didn’t help, here are some other reasons for a trunk light problem:
The light bulb isn’t fitted in properly
If this is the problem, give the bulb a turn or wobble or take it out and put it back once more.
Trunk light switch
The trunk light is triggered by a switch usually located somewhere on the locking mechanism for the trunk. It may be either on the lock itself or near the latch.
Mostly due to material fatigue or physical damage, the switch stops working. In this case, you’ll have to change the switch or even the whole locking mechanism.
One more option is that the switch may be blocked by filth and rust. In this case, using some contact spray or WD-40 spray may save the day.
Another place you should look when this happens is the wiring harness between the trunk and car body. It will be inside a rubber protective cover. Due to constant bending, a wire inside might break.
Filthy or rusty contacts
You’ll easily notice this problem when you pull out the trunk light housing. Rust and filth are usually located on the contacts holding the bulb in place.
With this problem, use some contact spray, sandpaper, or a screwdriver to clean or scrape the contacts. This happens mostly when there’s moisture in the trunk or on older cars.
Filthy or rusty connector
If the contacts are rusty, you should probably also check the connector. Best disconnect it and then take a look. When there’s a rust and filth build-up, best use contact spray to clean it. In worst cases, you may need to replace the whole connector.
As mentioned at the beginning of the article, you should check the electric input. If there isn’t one, the fuse is the first place to check. If you want to learn how to change a car fuse, click here for a separate article on that topic or watch a YouTube video.
Broken or damaged wire installation
This is a pretty rare problem and should be considered if there’s no electric input.
Places you should look at are where the wiring harnesses bend or go through tight spots. Also, if some previous intervention has been done (like bodywork), check those places too.
All of this may seem a bit complicated, but you’ll see that learning how to change a trunk light bulb is one of the easiest car repairs.
In practice, it takes about five to ten minutes on almost all cars.
Fixing the problem may take longer if the bulb isn’t the problem. But that’s another story that involves more time, patience, sometimes spare parts, etc.
But even this is not that complicated to solve, in most cases.
Regarding expenses, the usual one is only for a new light bulb which is cheap (even when made in quality).
All of this certainly beats digging around the trunk like a mole searching for the spare tire, things, tools, or else.
Written by: Sibin Spasojevic
Former car technician, life-long car and DIY enthusiast, author for Despairrepair.com
HOW TO CHANGE A TRUNK LIGHT BULB? YOUTUBE VIDEO