Symptoms
- Visible frost or ice crystals inside the headlight lens
- Fogging appears especially bad in freezing weather
- Ice may partially block light output
- Problem seems to worsen specifically in winter
Likely causes
- CommonExisting moisture inside the housing freezing in cold weatherThe same seal or crack issues that cause fogging become more visible as ice in freezing temperatures.
- CommonDegraded seal allowing continuous moisture entryA compromised seal lets in enough moisture over time to accumulate and freeze.
What to do
- Turn on the headlight and let it run to generate heat, which can melt minor ice buildup.
- Once thawed, check for any remaining moisture or standing water that indicates an ongoing seal problem.
- Inspect the lens and seals once the housing has warmed up and any ice has cleared.
- Note if this happens only in the coldest months, or continues as regular fogging in warmer weather too.
- Treat this the same as any other headlight moisture issue: identify the seal problem and repair accordingly.
- Avoid scraping ice directly off the inside of the lens, which isn't accessible without disassembly and could cause damage.
- Have a shop inspect and reseal the housing once you're able to access it without freezing conditions.
- Replace the housing if the seal issue is significant enough that resealing isn't practical.
Tools and parts
- Flashlight
Replacement headlight housing/assemblySearch: “headlight assembly for [your car make model year]”
When to call a pro
Ice inside a headlight is a clear sign of an underlying seal problem; have it addressed once the ice has cleared and you can properly inspect the housing.
Safety
Generally low risk
Generally low risk for a careful person. Stop if anything looks different from what this guide describes.