Car Headlight Condensation

Ethan Everett
Ethan Everett used Ask the Experts™
How do I remove condensation from the inside of a car headlight?
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Bill PrewIT / Software Engineering Consultant
Top Expert 2016

Typically you need to let it dry.  The issue is often caused initially because water or moisture can enter the headlight assembly when it shouldn't able to.  You need to check it thoroughly for cracks or poor seals and take care of those.  Also many assemblies have vent holes or tubes to allow moisture to escape, check those and make sure they aren't plugged.

Dr. KlahnPrincipal Software Engineer
Bill is right.  This wasn't a problem when headlights were unitized assemblies, but it sure is now.

If the assembly can be removed from the vehicle conveniently ("conveniently" being the critical word), then pull it out, remove the lamps and let it sit out in the sun for a while with the lamp holes up (moist air rises).  Don't try to dry it from the inside with swabs or paper towels; any fibers left inside will turn black and burn when the halogen lamps turn on.

If it's cracked then it may make more sense to just replace it with one from a junkyard.
IT Professional | Freelance Journalist | Looking for Opportunities
Distinguished Expert 2018
If you want to shortcut waiting for it to clear up on its own, just use something like a hair dryer to blow on the lens directly at its highest heat setting. Might take a fair while of blowing, but much quicker than just waiting for it to clear up on its own.

Hope that's helpful.

Regards, Andrew
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What is the make and model of your car?
I have a truck and one light shows moisture. It looks like replacing it from a parts yard may solve it totally or trying to dry the existing one will only be a temporary cure. There are Pull A Part locations all over the country. Maybe in your area.
Does the headlight have an LED bulb rather than the traditional halogen bulb?
If so, the reason is that the LED bulb does not get hot enough to get rid of the condensation.
I've had the same problems with my headlights and tail lights since manufacturing moved to LEDs.
Assemblies are rarely absolutely airtight.
Ethan EverettSTEM High School Student


Thanks to all who answered!

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