What’s the Best Way To Fix Condensation in Headlights?

How Are Headlights Made?

Headlights are comprised of two pieces the headlight housing and the headlight lens.  The headlight housing contains the headlight bulbs and the electrical connections to allow your headlights to illuminate.  Headlight lens’ are designed to keep water and other debris from entering the headlight housing.  Headlight housings and headlight lenses are then sealed together using a silicone sealant that’s designed to keep water from entering the headlight assembly.  But that silicone sealant can become brittle and crack over time allowing condensation or water to form inside of your headlights.

Why Is There Condensation in my Headlights?

Condensation can get into your headlights in a couple of different ways.  Since headlights generate heat most headlights have vents that allow hot air to escape the headlight and cool air to enter.  These vents are usually the cause of condensation inside of headlights.

If you didn’t know condensation occurs when hot air rises and then cools down, losing its ability to hold water vapor. As you drive around the headlight housing will become hot (causing air to rise inside the headlight) because of the heat generated by the headlight bulbs.  As your car’s headlights cool off after you are done driving the outer lens will cool faster than the interior headlight housing which then cools down the rising water vapor and causes condensation to form inside of the headlight.

Another way that condensation or water can get inside of the headlight is a cracked or broken seal on the headlight assembly.  The headlight lens will be mounted on the headlight assembly with the outer edge sealed with silicone sealant.  If that silicone sealant cracks or was improperly applied when the headlight was made it can allow large amounts of condensation or water to enter into the headlight which is not good for the headlight overall.

Is Condensation in Headlights Normal?

Small amounts of condensation inside of headlights is normal because most headlights have vents that allow outside air to enter the headlight.  But if you are experiencing large amounts of condensation or water buildup inside of the headlight then you need to inspect your headlight to see what is causing so much water or condensation to form.  Causes can range from a cracked headlight lens, improperly installed headlight bulbs, or a cracked seal around the headlight assembly.

How to Fix Small Amounts of Condensation in Headlights?

To get rid of small amounts of condensation you can park your car in the sun to allow them to heat up and allow the condensation to escape through the vents on the back of the headlight assembly.  If it’s not sunny or hot outside currently you can also try turning on your headlights, doing so will generate heat and cause the condensation and moisture to escape through the headlight vents.

Another trick to get rid of small amounts of condensation in headlights is taking your car for a drive.  This will push air into the engine bay and into the vents of your headlights, effectively getting rid of the condensation in them (more effective if you drive with your headlights on).

If your headlights are consistently having condensation form inside of them then you would want to inspect the vents on the back of the headlight to make sure that there is not something blocking the vent not allowing air to escape from the headlight.  Just make sure that if there is something plugging the vent that you try to extract the debris without pushing it into the headlight assembly, you want any debris to exit the headlight assembly not be pushed inside of it.

One important note is that you do not want to turn on your headlights if there is more than a small amount of condensation on the inside headlight lenses.  If you notice puddles of water at the bottom of the headlight or near the headlight bulbs you wouldn’t want to turn on your headlights because it would risk shorting out the headlight bulb and potentially the headlight housing.  If your headlight housing shorts out then you’d need to buy a whole new headlight unless you plan on having the headlight housing replaced.

How to Fix Large Amounts of Condensation in Headlights?

So now you know what you should do if you have small amounts of condensation in your headlights, but what should you do if there are large amounts of condensation in your headlights?  For large amounts of condensation, you would want to inspect the headlight to see if you can determine what is allowing so much water or condensation to enter into the headlight.

****It’s important to not turn on your headlights if you notice water inside of the headlight, doing so can short out the headlight bulb or headlight when this happens the bulb or headlight will need to be replaced.***

Inspect the seal between the headlight lens and the headlight housing to see if you notice any cracks in the silicone sealant.  Look at the headlight lens for cracks in the lens.  Check the headlight bulb to make sure that it’s installed correctly and doesn’t have any gaps around it to let water in.

Some headlights will have covers over the back of the high or low beam bulbs.  If your car has these sorts of protective covers then you’d also want to inspect them to make sure they are attached to the back of the headlight correctly.  Also, make sure that your headlight isn’t missing one of these protective covers.  If it looks like something is missing from the back of the headlight look at images of replacement headlights for your car to determine if your headlight looks different from the replacement headlight.

Once you’ve determined what’s allowing large amounts of condensation or water into your headlight then you need to get the problem fixed by either repairing or replacing the headlight.  Depending on the age and condition of your headlights you’d want to consider replacing one or both headlights with new ones.

How Much Does It Cost To Fix a Headlight with Condensation?

The cost to repair or fix a headlight that suffers from excess condensation will come down to what is causing the excess condensation in the first place.  If the silicone seal around the headlight has failed then you can remove the previous silicone seal and replace it with new silicone, new silicone sealant can be picked up for less than $10.

I’ve never resealed a headlight before so I can’t speak to the difficulty of it but after watching the process it doesn’t seem all that hard if you are somewhat mechanically inclined.  On some cars, it’s going to more difficult to remove the headlight from the car than it will be to replace the silicone sealant.  To check out a Youtube video of the process watch the video below.

If the vents on your headlight are plugged then you can usually clean them out with tools that you have on hand, a shop-vac or vacuum is preferred to keep debris from entering into the headlight assembly.

If your headlight lens is cracked you have the option of buying a new lens and mounting the new headlight lens to your headlight housing, but it may be easier to just replace the headlight with a new one.

When To Replace Your Headlights

Sometimes it just makes sense to replace your headlights with new headlights provided they don’t cost thousands of dollars to replace.  Headlight lenses will become faded and yellow from the UV rays from the sun over the years.  If your headlights are old, cracked, and faded then it may make more sense for you just to replace your headlights with new ones instead of repairing them to remove condensation.  Typically with new headlights, you won’t have a problem with too much condensation getting into them.

 

Can Car Fail MOT Inspection for Condensation in Headlights?

Yes, your car can fail MOT inspections for condensation in your headlights.  While this won’t be a problem if you have small amounts of condensation in your headlight it can be a problem if large amounts of condensation or water are building up inside of your headlights.  If you have a lot of condensation buildup in your headlight then you would want to figure out what is allowing water to enter your headlight and then get the problem fixed.

Condensation in Headlights After Car Wash

If you have condensation in your headlights after washing your car your headlight may have a leak at the seal between the headlight lens and the headlight housing.  Inspect the seal around your headlight housing to cracks or areas where water could enter into the headlight.

Condensation in Headlights New Car

New cars are not immune to getting condensation in their headlights.  Since most headlights manufactured today will have vents on the back of them they can allow condensation to form inside of the headlight.  It’s normal for small amounts of condensation to build up inside of your headlights, it should go away on its own if placed under direct sunlight.