Symptoms
- Visible fog or water droplets inside the fog light lens
- Fog light seems dimmer than normal
- Fogging appears mainly after rain or washing
- Bulb burning out more frequently than expected
Likely causes
- CommonDegraded housing sealFog lights are mounted low and exposed to more road spray and debris, accelerating seal wear.
- CommonCracked lens from road debris impactTheir low mounting position makes fog lights more vulnerable to rock chips and debris.
- PossibleBlocked or missing vent on the housingA blocked vent can trap moisture that would otherwise evaporate.
What to do
- Turn on the fog light and let it run for a while to see if minor condensation clears with heat.
- Inspect the lens closely for cracks or chips that could be letting water in directly.
- Check the seal around the housing for visible gaps or degradation.
- If moisture is minor and clears with use, monitor it over the next few weeks for changes.
- Remove the housing if accessible to dry it out fully and inspect the vent for blockages.
- Reseal with a proper high-temperature sealant if a specific gap is identified.
- Have a shop replace the housing if fogging is persistent or the lens is cracked.
- Consider protective film for the front of fog lights if they're prone to debris impact in your driving conditions.
Tools and parts
- Flashlight
Fog light housing/assemblySearch: “fog light assembly for [your car make model year]”
When to call a pro
Given their low mounting and exposure to debris, cracked fog light lenses are common; a shop can quickly assess if resealing or replacement is needed.
Safety
Generally low risk
Generally low risk for a careful person. Stop if anything looks different from what this guide describes.