The brake lights on your car are a way to signal other drivers your intentions and tell them what you are about to do. It is essential that these work properly, in case you need to slow down for any reason while avoiding getting rear-ended. There is also the fact that faulty brake lights can get you a traffic ticket. You can avoid all that by the testing these things every now and then, and especially before the low-light time of the year sets in.
All it takes is having someone watch the back of the car while you press the brake pedal. If you are doing this by yourself, place a mirror behind the vehicle, and take it from there. There are three brake lights to check in modern cars – both of the side rear ones and the one in the back window.
If They are Not Working
The brake lights are based on the electrical system in your car, and if any of the switches or fuses malfunctions, these lights could fail to function properly. This can be traced back to one of the below three things.
- The system fuse is blown.
- The bulbs have burned out.
- The wiring switch broke.
The Brake Light System Fuse
If all three of your brake lights are out, then the individual bulbs are likely not the problem; chances are the electrical system is on the fritz. Sometimes this is because of something as simple as a blown fuse.
- Check the power distribution center (or fuse box) of your car, which is located under the dashboard. If you have trouble finding this, check your car’s user manual to know the exact spot.
- Turn on the ignition and get a connect test light. Ground the latter.
- Press the tester’s tip to each end of the fuse, and press the gas pedal. If the test light illuminates, that means the fuse is working fine. Otherwise, move on to the next step.
- Press the tester’s tip to one side of the fuse, and again, press the gas pedal. If the test light illuminates, that means the fuse is faulty. If it fails to light, then a replacement is definitely due.
- Put in a new fuse and perform the same test as above. If it fails to light, then you know the entire circuit is shorted out, and will require a mechanic to fix.
The Brake Light Bulbs
Replacing a faulty or useless brake light bulb is very simple. Below are the things you need to do.
- Go in through the fender or the trunk (check your manual), and locate and remove any bulb trim or casing.
- Detach the bulb as you would normally, and check the housing and filament.
- If the filament is blackened, or if the bulb is cracked, you will need to replace the latter.
- Check the other lights with a friend or using a mirror, performing the same steps as above.
- After putting in new bulbs, check those as well. If they fail to work as they should, it points to a faulty bulb socket, which would require a mechanic to fix.
The Brake Light Switch
After looking at both the fuse and the bulbs of your brake lights, and finding them working perfectly well, the next logical place to check is the brake light switch. This mechanism is responsible for completing the brake lights’ circuit, and makes up an elementary two-wire switch. In that, one wire has control of power going in, while the other manages power going out. You can find this switch placed near the brake pedal.
- Grab the test light, and like you did before, ground it.
- Place the test light sensor on one of the wires. Press the gas pedal and see if the test light illuminates.
- Check the other wire in the same way. If neither lights up, that shows the brake light switch is faulty, and needs replacing.
- If the switch is complicated, and has three or more wires, check the car manual to figure out which ones are the “primary out” and “primary in”.
Sometimes, you will find that the brake light is not working right, although the brake system fuse, brake bulbs, and brake switch are all performing well. This may mean your car has a different system that requires checking. One example is where the run indicators and brake lights are connected to each other, which means combined fuses that render the above checks useless.
Some cars even have dedicated control modules for the brake lights, while others with integrated computer systems provide the option to do onboard diagnostic scans to locate problems. Whichever it is, you should call a technician if things became too complicated or difficult to handle.