A little fog inside a headlight on a humid or cold morning is normal: headlights have vents, and moisture can condense on the cold lens and clear once the lights warm up. Water droplets that stay, or water pooling in the bottom of the housing, mean a seal has failed or the housing is cracked, and that moisture can damage bulbs, LEDs and reflectors over time.
Normal condensation vs a leak
| What you see | Likely cause |
|---|---|
| Light haze that clears after driving with lights on | Normal venting |
| Large droplets that never clear | Failed seal or blocked vent |
| Standing water in the housing | Crack or failed seal |
| Moisture after a car wash only | Seal around the bulb cap or lens |
Headlight condensation fix
- Remove the bulb caps and let the housing dry with the lights on or in warm, dry air; silica gel packs inside the engine bay near the housing can help.
- Check the bulb caps and their seals are seated properly.
- Inspect the lens and housing for cracks, especially after stone strikes.
- Reseal the lens-to-housing joint if the seal has failed, or replace the housing if it is cracked.
- Make sure the vent tubes are not blocked or pinched.
Preventing condensation
- Avoid aiming pressure washers directly at headlight seams and vents.
- Replace bulb caps and seals whenever you change bulbs, and make sure they click fully into place.
- Repair stone chips and cracks in the lens early, before water gets in.
- Keep vent tubes clear of dirt and routed as designed so the housing can breathe.
Why it matters
Persistent moisture corrodes connectors and reflective surfaces, shortens bulb and LED life and scatters the beam, which reduces visibility and increases glare for other drivers.
Condensation in LED headlights
LED headlights run cooler at the lens than halogen headlights, so they can take longer to clear normal fog. The same rules apply: haze that clears is normal, while droplets or pooling indicate a seal problem.
After installing new headlights
Seat every seal and cap carefully, route vent tubes as designed and aim the lights; see how to adjust headlights and projector vs reflector headlights. Replacement assemblies such as our Molded Innovations sequential LED headlights for the WRX ($934.99) come as sealed units.
When to replace instead of repair
A cracked lens, a housing that keeps filling with water after resealing, or corroded reflectors are reasons to replace the assembly. Replacement is also the chance to move to a better beam design.
More guides: LED vs halogen headlights.
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