How to fix brake lights? This is the first question that comes to mind once you’ve concluded that they’re not working.
It might be that you’ve noticed this problem when parking in the garage and the bright red reflection is missing when you press the brake.
Another common situation is that other drivers who drove behind you angrily come to you and warn you that you don’t have any brake lights.
Whatever the situation, this article will try and help solve the problem. It will first show how to find what’s wrong and then how to perhaps solve it.
Besides this article, you also have a YouTube video on the same topic which you can watch at the end of this article or on our YouTube channel.
WHAT WILL YOU NEED TO FIX THE BRAKE LIGHTS?
You’ll need either a simple tester or a multimeter. Also, you’ll probably need a spare light bulb.
Light bulbs are the most common problem but there may be other issues. All depending on the problem, you might need a spare brake light switch, spare connectors, or else.
But first, see what the problem is and then buy what you need.
HOW TO DIAGNOSE THE PROBLEM?
The first thing to do if you want to properly learn how to fix brake lights is to properly diagnose the problem.
The usual starting point is the tail lights.
So, the first thing you should do is gain access to the rear of the tail light, take out the bulb holder and make an inspection.
If the light bulb is the problem you’ll probably see that the glass balloon is black or dimmed. Besides this, the filament may be broken or burnt out.
However, if the bulb is OK, then you’ll have to take out the bulb and use the tester or multimeter to see if any electricity is coming to the bulb. If there isn’t, then you’ll have to search further down the line.
So, this is ground zero for solving the problem.
Here’s also some advice that may come in handy, especially if you don’t have a tester or multimeter.
If you see that only one brake light works, check the bulbs first and after that the fuse.
Do the same if both brake lights don’t work but the third brake light does.
But if all of the brake lights don’t work including the third brake light, then you should consider checking the fuse, brake light switch, or else.
HOW TO FIX BRAKE LIGHTS? COMMON CAUSES AND SOLUTIONS
1. BAD OR BURNT OUT BULB
This is by far the most common reason and the first thing to check out when you want to learn how to fix brake lights.
The standard bulb for cars is the single filament 12 volt 21-watt bulb or the double filament 21 and 5-watt bulb. The double filament is when the position and brake light is combined in one place in the tail light.
Just to mention that all of this of course does not apply to LED taillights.
You’ll easily notice the bad bulb by having either a broken or burnt-out filament or even a dim or black glass balloon.
2. BLOWN OUT BRAKE LIGHT FUSE
If you’ve concluded that the bulb is OK, next in line is to check the brake light fuse.
Especially do this if you’ve seen that there isn’t any electric input coming to the bulb holder.
The fuse is easy to replace. The most important thing to know is where the fuse box is located and what is the exact fuse for the brake lights.
Also and most important, always replace the burnt-out fuse with the exact same one in terms of amperage. For instance, don’t put a 25 amper fuse in place of a 10 amper one.
Remember that the fuse goes out for a reason. Something may be critically wrong and needs to be checked out as soon as possible.
3. BRAKE LIGHT SWITCH
When the bulb and fuse are OK, the next checkpoint is the brake light switch.
This switch is activated when you press the brake and it’s usually located on a bracket just above the pedal.
In order to reach it, in most cases, you’ll have to take off the covering panel above the pedals.
After that, you’ll have to use the tester or multimeter to see if there is electric input coming to the switch.
If there is input going into the switch but none coming out, the switch is the problem or maybe the connector on the switch.
Replacing it, in most cases, isn’t that much of a problem. The usual scenario involves disconnecting the wiring connector, twisting the switch counterclockwise from the bracket, inserting a new one, and tightening it clockwise into place.
The bigger problem, in most cases, is accessibility. In order to replace it, you may have to lay under the pedals on the floor which can be very tiresome.
4. CHECK THE CONNECTORS AND WIRING
One more place you should take a look at if you want to learn how to fix brake lights.
If all of the previous checkpoints are OK, then you should check the connectors and wiring.
Two first places you should look at are the bulb holder and the connector on the bulb holder.
Both of these may get dirty, corroded, or loose over time and prevent good contact.
Another place to look is the rubber sleeve through which the wiring goes from the car body to the tailgate. Over time, because of material fatigue and bending, the wires may break inside the rubber sleeve causing the brake lights to stop working.
Especially check if the tail light or parts of it are located on the tailgate.
Also, you should check the wiring and connections if some bodywork or other kind of repairs have been recently done.
Sometimes there might be a damaged wire, loose connector, bad contact left behind, or else.
Fixing the problem is relatively easy. In most cases, it involves cleaning or replacing bad connectors, tightening bad connections, mending or replacing parts of the wiring installation, or else.
The bigger issue in most cases is finding the exact spot where the problem is.
5. BAD TRAILER CONNECTOR
If you have a trailer connector on your car check its condition and connections.
This goes double if the brake light fuse is burning out all the time.
The main reason for problems is that the connector is exposed to weather and road conditions all the time. This makes it prone to rust, loose or damaged connections, broken cables, or else.
Also, using a trailer that has a mismatching wiring connection will cause problems. If the wiring is not the same on both connectors it will cause a blown fuse or the signalization won’t work properly
If the trailer connector is causing the problem, you can try and use some contact spray and clean it.
But if you see that it’s badly damaged, the best solution is to replace it completely.
There is one more reason for a brake light problem you should consider although it’s very rare.
That reason is a faulty ECU.
You should check this out especially if you’ve had recent major electrical problems.
These problems would be with the alternator (namely high alternator voltage), major short circuits, not connecting the battery properly, or else.
In the end, there’s one more very important thing you can do from time to time.
That is to take a look if the brake lights are working. I’m mentioning this because It can pass days if not months until you realize that they’re not working.
No need to say how dangerous this is both for you and other participants in traffic.
The moment you notice the problem, solve it as soon as possible.
Remember that lots of drivers can’t spot on time that you’re brake lights don’t work. If they don’t, you may well cause an accident.
Written by: Sibin Spasojevic
Former car technician, life-long car and DIY enthusiast, author for Despairrepair.com
HOW TO FIX BRAKE LIGHTS-YOUTUBE VIDEO