How To Get Condensation Out Of Headlight

This is our guide on how to get condensation out of a headlight. 

Moisture from the air can build up in your headlight over time. 

This is the condensation you see under the surface of your headlight, and, among other things, it causes a dim, blurry beam, and could even reduce the lifespan of your headlights. 

While professionals will be more than happy to fix the problem in exchange for money, if you have a couple supplies and a can-do attitude, you can get condensation out of a headlight at home.

We’ve been working on and reviewing headlights for over a decade, so suffice to say, we know a thing or two about them. If you aren’t sure how to get the condensation out of your headlights, leave it to us. 

Keep reading for more information on how to get condensation out of a headlight. 

What Causes Condensation To Build Up In Headlights 

It’s pretty easy to understand why condensation builds up in headlights. Put simply, a headlight bulb gets hot with regular operation. Really hot. 

All of that heat needs to be evacuated out of the headlight assembly, which is why there are tiny vents in the assembly to let warm air out and also help cool the headlight bulb with cool air from the outside. 

When outside air enters the headlight assembly, it brings with it a lot of moisture in the form of water vapor. 

As the outside surface of the headlight is colder than the inside, water condenses on the inside of the headlight lens. 

What You’ll Need To Get Condensation Out Of A Headlight

There are a couple things you’ll need if you want to go the DIY route of getting condensation out of a headlight. 

Vacuum Cleaner

We’ll be using a vacuum cleaner to suck out the condensation and damp air that is stuck inside your headlight assembly.  

Hose Pipe

This can be a standard hose pipe that you can buy at any hardware store or online. If you have a dehumidifier unit, you might already have one lying around that you use for draining the tank into the floor. 

You shouldn’t need more than a few feet of hose pipe, say 5 or 6, so don’t go buying too much!

Duct Tape

We will use the duct tape to ensure that the vacuum cleaner and the hose pipe seal properly. 

Hair Dryer

You will need to use a hair dryer to replace the humid air that the vacuum sucks out with fresh air that is not as moist. 

How To Get Condensation Out Of Headlights

Alright then! Now that you’ve gathered all of the supplies, let’s get cracking. Follow this step-by-step guide to get condensation out of your headlights. 

Step 1: Remove The Bulb From The Headlight Assembly

This method doesn’t require you to remove the entire headlight assembly, but you will need to remove the headlight bulb from the back so you have a place to route the hose inside. 

You can remove the headlight bulbs pretty easily for most cars. The process might differ a bit from vehicle to vehicle, and the owner’s manual might need to be consulted, but that’s pretty much it. 

Step 2: Connect The Hose Pipe To The Vacuum Cleaner

Next, you need to connect the hose pipe to the vacuum. Use the narrowest vacuum accessory you have. This might still be quite a bit wider than the hose pipe, so you will have to use duct tape  to make sure the connection between hose pipe and the vacuum seals properly. 

Step 3: Route The Hose Inside The Assembly

Once one end of the hose pipe is connected to the vacuum cleaner and sealed properly, route the other end into the hole where the headlight bulb goes in. Make sure the hose goes far enough into the headlight assembly that it can effectively remove all of the moisture and air. 

Step 4: Position The Hair Dryer Next To The Headlight Assembly’s Vents

The vacuum will remove moist air and condensation from the headlight assembly, but you also need to replace it with fresh air to improve circulation, and make the process a bit faster. 

This is where the hair dryer comes in. Locate the headlight vents, and place the hair dryer right against them. You might have to remove a small rubber boot that is covering the air vent, but otherwise, this is another simple step. 

Step 5: Turn On The Vacuum Cleaner And The Hair Dryer

Now, turn on both the vacuum cleaner and the hair dryer. Start out with low speed settings for both and leave the whole setup to run for a while. As the vacuum evacuates the damp air and condensation, it is replaced by fresh air from the hair dryer. 

You should start to see the headlight clear up and condensation move out of the assembly. The time it takes for the process to be effective will vary depending on the amount of condensation in the headlight, the weather, and a couple other factors. 

Generally speaking, you should start to see some improvement after the setup has been running for about 15 or 20 minutes. If not, try increasing the speed of the vacuum cleaner and the hair dryer. 

Once all of the moisture and condensation has been cleared out of the headlight, turn off the vacuum and the hair dryer, replace the bulbs, and you should be good. 

How To Prevent Condensation Build-Up In Headlights

Condensation buildup in headlight assemblies isn’t really that common on modern cars. The vents inside the headlight are sealed with rubber boots that prevent moisture from entering. 

If you are experiencing condensation in your car’s headlights, it is probably a sign that the vents are not sealing properly which lets in moisture. Alternatively, the vents could be clogged with dirt, road grime, or biological matter such as mouse droppings or insects. 

So, to prevent condensation from building up in your headlights, make sure the vents in your headlight assembly are not clogged, and that the rubber parts of the vent are sealing properly. 

Another common cause of excess condensation in your headlights is a cracked or damaged headlight. This is a bit trickier to fix, since you will have to locate and patch the crack. Or if the crack can’t be fixed, you might even need a new headlight. 

If you want to prevent cracks in the headlight that could cause condensation buildup, consider protecting the headlight with a polycarbonate shield or a clear plastic film that goes onto the headlight itself. 

These should offer protection against small rock chips, road debris, and other stuff that can cause cracks in the headlight. 


So, if your headlight has a lot of condensation built up in it, it could be due to a crack in the headlight, a clogged headlight vent, or a headlight vent that isn’t sealing properly. 

You can easily get the condensation out of your headlight at home, with only a couple supplies. However, if the problem is due to a larger crack in the headlight, you might even have to replace the entire headlight assembly. 

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Richard Nickleson is the author and owner behind Headlight Reviews. He first started the site as a hobby to share his insights on car parts and specifically headlight bulbs, but it soon ballooned and now he writes on all topics surrounding headlights bulbs. If you've got a bulb question, contact Richard here.