As you drive down a dark road, you may notice the headlights give off a dim, unfocused beam. If your car’s headlights also appear yellow or dull in appearance, these signs indicate that moisture has built up inside or the material has started to oxidize.

Both inconvenient and unsightly, foggy headlights can also affect visibility up to 50 percent, potentially compromising safety. In certain areas, you might even be ticketed for having foggy headlights. If you’re dealing with this headlight issue, understand how it develops and learn how to improve the clarity and brightness.

What Causes Foggy Headlights?

Once made of glass, most modern vehicles have headlight lenses or cases made of polycarbonate. This thicker, more scratch-resistant plastic is durable and less likely to crack than glass.

However, polycarbonate succumbs to the same issues that other plastics experience. Repeat exposure to UV rays and the elements causes the material to break down and develop a yellow, cloudy or cracked exterior with small pock marks and dents. This factor also affects how well the material absorbs the bulbs’ blue light, resulting in less brightness and focus.

Multiple factors contribute to these changes:

• Oxidation: In response to repeat exposure, oxidation first wears down the coating that covers the headlight before it gets to the polycarbonate underneath. Cloudiness and yellowing result from repeat exposure to air and UV rays.
• Debris: An abrasive effect that further wears down the coating and creates additional pitting. Based on where you live, rock salt and gravel can also accelerate this process.
• Dirt: Can build up in a thin layer on your headlights, holding onto road debris and chemicals. This development increases cloudiness and lack of focus.
• Water Vapor: Can accumulate inside the headlight casing due to the cracks and pitting that develop with time. Condensation gathers inside, which affects the beam focus. This is especially pronounced with halogen bulbs. Water vapor may also indicate the vents next to the headlights have become blocked. If this issue is ignored, the car’s electrical system may eventually be affected.

Addressing Foggy Headlights

Early-stage issues can be addressed from home. A light polisher that won’t wear down the exterior coating can be applied to remove dirt and yellowing. Be sure to apply this solution out of the sun. Also wash your car with water and an automotive-specific soap every few months to remove any dirt and acids that may have started to gather on the headlights’ exterior. Parking in a shaded area with limited UV exposure can help reduce future oxidation.

Yet it’s important to understand that results from these at-home techniques only last a month or two. Advanced yellowing also requires sanding down the headlight and applying a clear coat. For this reason, professional headlight restoration is encouraged to remove existing oxidation and protect the headlight against future oxidation, yellowing and surface damage. This process starts with sanding and polishing to remove dirt, pitting and yellowing, then sealing the headlight to prevent interior moisture buildup.
 
Trust DaSilva’s Auto Body for headlight restoration and other repair services to improve performance. Contact us to schedule an appointment today.