When your vehicle only has one headlight out, you probably just have a bad headlight bulb. However, if both of your headlights aren’t working, and they both went out at the same time, you have a bigger problem!
Unless you have a bad fuse or a bad relay, it’s practically impossible for all of your headlight bulbs to go out at the same time. So what’s causing this problem? If you’d like to find out, keep reading!
Why Won’t My Headlights Turn On?
When both your vehicle’s headlights won’t turn on, maybe you’ll get lucky and find that it’s just a fuse. But even so, something bigger usually makes a fuse blow. You could be looking at a bad headlight relay, dimmer, switch, or even some faulty wiring. Either way, be prepared to seek out an auto repair shop or dealership.
If your headlights won’t turn on, your vehicle is obviously in no condition to drive after dusk. Read this article for a list of things that might be causing the problem and what you can do to fix it!
What Should I Do If My Headlights Won’t Turn On?
#1 Check Headlight Bulbs:
Although it’s highly improbable that both of your headlights will go out at the same time, there is a situation where this can seem like it happened.
That is, you may have burned out one headlight a while back and never noticed it.
When the second headlight goes out, the difference is too hard to not notice the issue.
So, although highly improbable, check to see if the filaments on both of your headlights are still intact.
If they aren’t, replace the bulbs, and if they are, you have a bigger problem.
#2 Check Connections:
It’s possible that some heavy bumps or rough driving terrain have rattled a headlight wiring connection or a bulb socket out of place.
Therefore, make sure everything seems intact from the headlight bulb socket all the way to the fuse box.
Any further electrical diagnosis should be left to your technician/dealership.
Electrical problems can get very complicated and hard to deal with. Therefore, you might end up causing more harm than good by tackling the problem yourself.
#3 Check Fuses:
If both headlights went out at the same time, then more than likely, this will be your problem.
You can use your owner’s manual to find the fuse box and the provided diagram to find the fuse.
Most cars provide you with a fuse puller, which will help you get the headlight fuse out, so you can check it.
You should be able to tell if the headlight fuse is blown just by looking at it.
#4 Bad Relay:
A bad relay is much like having a bad fuse, you will even find the headlight relay in the same place you find the headlight fuse, in the fuse box.
The relay can either cause your headlights to not turn on or not turn off.
The best way to figure out if you have a bad relay is to replace it with another relay from the fuse box that matches it exactly.
If your headlights work properly, you know you have a bad relay, but if your headlights don’t, then you have another problem.
Important: If you use another relay from your fuse box, and your headlights work properly again, you still have to replace the relay.
The relay you borrowed to work your lights properly is used to work something else vital to your vehicle’s running condition.
#5 Headlight Switch: If you have no power reaching your relay in the fuse box, then you probably have a bad headlight switch.
This is another one of those problems you probably don’t want to tackle by yourself.
This job is a little more involved, especially if you have a headlight switch on the steering column.
This would be best to just have a professional take care of the problem for you.
Can a Fuse Stop Headlights From Working?
Fuses are designed to blow so that they can stop any dangerous high voltage electrical current from getting to a more expensive and important part of the vehicle.
When a fuse blows, it creates a break in the electrical current, not letting anything electrical past that point.
If your headlights are within the circuit where the fuse was blown, then yes, your headlights won’t work.
What Are the Symptoms of a Bad Headlight Relay?
When you have a bad headlight relay, you will either have headlights that won’t turn on, or headlights that won’t turn off.
Which situation you get will usually be determined by whether your headlights were on or off when the relay went bad.
How Much Does It Cost to Replace a Headlight Relay Switch?
Headlight relays don’t usually cost that much – anywhere from around $14-$40 for a normal vehicle and normal size relay.
This is something you can probably do on your own if you have an average vehicle.
However, if you can’t do it on your own or don’t want to, the cost of the relay will still be fairly cheap, but labor cost will get you for around $100 for a couple minutes of work.
Does Each Headlight Have Its Own Fuse?
On some more expensive or exotic vehicles, each headlight could have its own fuse.
However, for most vehicles, you will have a separate fuse for the high beams and one separate fuse for the low beams.
How Much Does a Headlight Fuse Cost?
The price for a headlight fuse for your vehicle will vary. It will all depend on what size fuse your vehicle uses for the particular circuit.
A headlight fuse could cost you anywhere from $5-$10, to $20-$45.
Important: It’s not uncommon to see the benefit in buying a smaller fuse to save money, but this is not a benefit at all.
Fuses are designed to help protect more expensive parts of your vehicle.
If you go too small, you will constantly have a fuse that blows, costing you more money.
Also, if you go too big, the fuse will let dangerous currents through the headlight circuit without blowing, costing you even more money.
To learn more, you can also see our posts on headlights won’t turn off, are LED headlights better, and how do automatic headlights work.
If your headlights go out at the same time, you most likely have a bad relay or a bad fuse. These are easy fixes that shouldn’t cost you too much and can be done by the most novice of car owners.
When you have one headlight out, this most likely means you have a blown bulb, and you can fix that problem by replacing the bulb. If you’re experiencing other problems like a headlight switch or an electrical problem, I would suggest you head to your auto repair shop or dealership to have it fixed.