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Is it normal for condensation to happen inside my car's headlights?

Is this something to worry about?

Good day, sir. I would like to seek your advice and expertise regarding moisture and condensation in the headlights of my newly bought Mitsubishi Montero Sport GLS Premium. It happens every time it rains or during car-wash day.

I brought it to the dealer. They performed a leak test, and condensation developed. They said it is a natural phenomenon and not a defect based on a letter coming from Mitsubishi. But why does it only happen to one headlight when both get exposed to rain and water? The dealer couldn't address this.

They said they will only replace it when water remains inside the headlights. If condensation disappears, then it is normal according to them. Kindly share your opinion and expertise on this matter.

Thanks and more power,


Hi, Ferdinand. Condensation inside headlights is not uncommon and it's not something to worry about. It is a normal occurrence. This is because modern headlight housings aren't sealed airtight. Ventilation passages are built into the headlight housing to let moisture in and out. The purpose of these vents are to allow pressure and/or temperature differences between the inside and outside of the housing to more or less equalize so they won't lead to the bulb and/or the housing itself from developing fissures and malfunctioning.

When there is a variance in temperature between the outside and the inside of the headlight housing such that the external temperature is lower than the interior of the housing, precipitation will usually occur inside. Once the external temperature rises, the precipitation will evaporate and your headlamps will clear up.

The reason it happens to only one headlight could be caused by a number of reasons or a combination thereof. It could be the way the moisture enters the vents from the top or moisture from the bottom coming in through the fender liners and into the headlight bottom vents, which may not happen to the other headlight. But the point is that condensation is a normal occurrence, which isn't anything to worry about.

Now, if it progresses beyond condensation and you find that water accumulates inside your headlamps making it resemble a little aquarium, then that's the time to check the gaskets or if any fissures have developed in your headlight housing that's letting water in.

Hope this answers your query, Ferdinand!

Joey Bernardez

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