Symptoms
- Headlight lenses look cloudy, foggy, or yellowed
- Headlights seem noticeably dimmer than they used to
- Reduced visibility at night despite bulbs being new
- Lens looks rough or hazy to the touch
Likely causes
- CommonUV oxidation of the plastic headlight lensSun exposure breaks down the clear coating on plastic headlight covers over years, causing yellowing and haze.
- CommonDirt and road grime buildup on the lens surfaceA layer of grime can reduce light output even without permanent damage.
- PossibleAging bulb producing less light outputOlder halogen bulbs naturally dim somewhat over their lifespan.
- PossibleMoisture or condensation inside the housingInternal fogging can also reduce apparent brightness.
What to do
- Wash the headlight lenses with soap and water first to rule out simple dirt buildup.
- Inspect closely for yellowing or a hazy, rough texture, which indicates UV oxidation rather than just dirt.
- Use a headlight restoration kit, following the included instructions to sand, polish, and reseal the lens.
- Apply a UV-protective sealant after restoration to slow future yellowing.
- Consider replacing bulbs at the same time if they're several years old, for a bigger brightness improvement.
- Check for any moisture inside the housing, which a restoration kit won't fix and may need a seal repair.
- Repeat restoration every year or two in sunny climates to maintain clarity.
- Have a shop replace the entire headlight housing if oxidation is too deep to polish out or if there's internal moisture damage.
Tools and parts
- Headlight restoration kit
- Soap and water
- Microfiber cloth
- Painter's tape (to protect surrounding paint)
Headlight restoration kitSearch: “headlight restoration kit”
Replacement headlight bulbSearch: “headlight bulb for [your car make model year]”
When to call a pro
If the lens has deep cracks or the housing has internal moisture, replacement is more effective than a restoration kit.
Safety
Generally low risk
Generally low risk for a careful person. Stop if anything looks different from what this guide describes.