Headlights Not Working? Check These Solutions

Headlights provide multiple functionalities for us while we are driving. Of course, if you’re driving in the dark, headlights can light the way and make it easy for you to see, whether the darkness is caused by nightfall or by going through a tunnel or dark parking garage.

Additionally, headlights can also help other people see us. Not to mention, if you happen to have a failed headlight you risk being pulled over by traffic authorities. There are many reasons why headlights are extremely important, and it is vital to know what to do in the event that your headlights are not working.

How Do Headlights Work?

The good news is that headlight systems are simple when compared to other systems in your car. Most headlight systems are going to involve a fuse, switch, relay, and bulb. Depending on the age of your car you may also have adaptive headlights or running lights; however, even these more complex headlights systems work similarly.

When the headlights turn on, they activate a relay in the system. This relay is the connection between the battery of your car and your headlights. There are also fuses involved to protect the rest of your electrical system should there be a shortage. There are special relays involved if you choose to turn on your high beam lights. When one of these components (or many of them) stop functioning properly, you may find that your headlights no longer turn on.

Can I replace my headlights on my own?

In some cases, you may be able to fix your own headlights if they stop functioning. Particularly if the issue happens to be a burned-out headlight, you may be able to replace the bulb on your own with basic tools.

If the problem is more complex than this, you may be better off taking it to a mechanic as a mechanic has advanced electrical equipment. For instance, you may not have a voltmeter laying around at home, but your mechanic certainly does.



This is probably the most common issue with headlights: you come home and notice that one of your headlights isn’t working. The most common issue here is that one of the two bulbs has simply burned out. Even if both of your headlights were installed at the same time, this doesn’t necessarily mean that they will have the exact same life. In fact, it’s more common for one bulb to fail before the other as opposed to both failing at the same time.

Visual inspection may prove that one of your headlights has corrosion or damage at the site of the headlight connector. In the event that the electrical connector is simply not tight enough, you may find that pushing on it solves the problem.

However, you may want to take the time to ensure that outside forces are not at work. Generally speaking, a halogen capsule headlight lasts between 500 and 1,000 hours of driving in the dark. If your light has suspiciously failed before this amount of time, there may be something at work outside of the electrical system that is causing it to fail. Another red flag is condensation on the inside surface of the headlight. Sometimes the seal around the headlight can fail, and this leads to water leaking inside of the headlight. If this happens, then the headlight experiences a drastically reduced lifespan. In this case, fixing the entire headlight assembly is necessary to prevent leakage.


Both headlights suddenly ceasing to work is generally rarer than one headlight turning off. A voltmeter can help you check the level of power at the headlights. However, the issue causing the failure is usually going to be more complex than bad bulbs if both lights go out simultaneously. In this case, you may need to go through and test out the headlight fuses, switches, and relays.

The easiest of these components to check is the fuse. You need to read your owner’s manual to discover how your particular car operates, but replacing a blown fuse is relatively simple in most circumstances. It is very important to ensure that you are replacing the old fuse with a new fuse featuring the same amperage rating. If you replace the fuse and it blows again soon after, you likely have an issue somewhere else in the circuit.

If both of your headlights are not working and the fuse is not blown, you should experiment with the relay. The most basic way to do this is to shake it: if you hear rattling inside of the relay, this likely means that the relay has experienced failure. Discolored terminals on the relay can also be a red flag. If your headlights are not working but high beams are, it’s likely that the relay is the culprit.

In some cars, identical relays are used in circuits outside of the headlight system. In this event, you can exchange the headlight relay with an identical component to test it out. If this results in your headlights functioning again, then the problem is the relay and you can simply purchase a new one for installation.

If this does not fix the problem or if you find that your car has a different relay for the headlight system compared to other electrical components, you may need to take it into a professional for a diagnosis. More advanced equipment may be necessary to determine the problem.


If your headlights are still functioning but simply not as bright as they used to be, there may be a number of factors causing this. The first is that as headlights age, they often lose a bit of their brightness. You may find that simply replacing the bulbs fixes the problem.

Another issue could be related to the headlight lenses. Oftentimes, older headlight lenses may discolor or oxidize after a period of time. Additionally, the headlight lenses may simply be dirty, in which case it is time to clean the assembly. If your headlights are foggy, this may be caused by condensation on the inside of the lenses. Generally foggy headlights mean that you should fix or replace the headlight assembly.

Fixing headlights when they go out or go dim is of utmost importance. Safe driving depends on it, so fix any issues related to your headlight system today.

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