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Why Your Car Headlights Turn Yellow & How To Fix It

damaged and blurred headlight

Are headlights hindering your vision at night, and yet your car is still relatively new?

There’s a reason why this might be the case.

Before the 80’s, headlight covers were made of glass only to be replaced by polycarbonate plastic that is susceptible to weather conditions and ultraviolet (UV) rays.

If abandoned, plastic turns blurry and yellow, which in turn blocks light from the bulbs.

This process can be accelerated if you usually leave your car parked for long hours out in the open.

So let’s unearth some of the reasons why your headlights turn yellow and how you can stop the process from becoming worse and ultimately restored to new again, without the need for buying new and expensive replacements.

Time and weather conditions

headlight of a vintage car

These two are significant factors that influence a car headlights durability.

As a part of the exterior car features, lights are very vulnerable to harsh or severe weather conditions.

Extreme summer temperatures, bug guts, air pollution, and road salts can make the coating film to peel off.

Aside from weather conditions, it comes to a certain point where the polycarbonate lens begins to fade off as well.

Just remember that your car travels at fast speeds and the headlights make direct contact with these contaminants during each trip.

Production materials

As explained above, the materials currently used in the manufacture of automobiles are entirely different from those used in the 20th century – especially in the 70’s going backward.

This is something most drivers fail to understand.

These days, vehicle companies use hard or polycarbonate plastics instead of less permeable glass as it can be cheaper to produce for them, therefore lowering costs.

To guard against the porousness, these plastics are generally covered with clear coat films, but that doesn’t prevent oxidation from taking place.

Also, you may be using specific cleaning agents that are making your headlight to change colour by degrading the clear coat with harsh and aggressive chemicals.

Chemicals and dirt

car driving in the fog

If your car is always on the road, a thin layer of chemicals and dirt can develop over the headlight lenses.

This layer is likely to dim the lights and make clarity a definite issue as once these chemicals and contaminants evaporate, they can really etch into the layer protecting your headlight (with the help of the Sun and time).

That’s why it is always recommended to wash your car on a regular basis as to ensure that no pollutants are given the conditions to penetrate.

Water vapor

headlight with water vapor

When the air has a high moisture content, two things take place.

First, vapor will be created inside your headlight cover and then get trapped due to the air outside becoming dry.

When this happens, the vapor disperses the light penetrating through the polycarbonate lens, creating diffusion and yellow light patterns on the track that disrupt clarity.

Road damage

broken headlight

While cruising on poor quality roads, the debris and small rocks can pit on the polycarbonate lens of your headlights.

In turn, the gravel accumulated creates dents and scratches across the lens meaning light does not exuberate as clearly due to the refracting light across these dents and scratches, hindering light quality.

Don’t worry!

If your car headlights turn yellow, the whole car becomes dangerous to yourself, your family, pedestrians, and other automobiles.

In many countries, yellowed headlights can cost you a ticket penalty/fine of up to $250 or make your license revoked.

I am sure that’s the last thing you would want as we all know how dependent our lives are when it comes to using our car for groceries, work, and so on.

In terms of car maintenance, headlights are severe business and incorporate actual safety issues.

Light output is significantly affected when headlights turn yellow.

The beam coming out of the beacon is weakened and will cover less ground in front of the car.

Smaller lighted areas can lead to deadly accidents, notably if your vision is naturally decreased.

So rather than spend hundreds and sometimes up to $3000 eg BMW headlight (depending on your car make and model) on replacing your headlights, you can simply buy an aftermarket equivalent or have them restored.

Of course, the outcome you receive will vary from vehicle to vehicle depending on how severe the contamination is.

How to fix the problem

The most obvious thing to do is to park your car in the shade or with a cover.

A shady tree is a perfect spot for parking. If that option is unavailable to you when parking outside, position your headlights away from the sun to slow the oxidation process, and decrease UV exposure.

But what if your headlights are already dimmed and dull? Great question!

What you will need to do is wash the car with automotive pH neutral shampoo to clean the car of as much contamination as possible.

Once you have gently dried the car, you will want to use a clay-bar along with the car wash shampoo (for lubrication) to further decontaminate the surface.

A clay bar is a great way to remove any stubborn pollutants in a non-abrasive way.

Once you have dried the headlights once again, you will want to buff the headlights with a Dual-Action Polisher with some polishing compound or alternatively with sandpaper.

You essentially want to ‘exfoliate’ the clear coat and smooth out the surface while removing the oxidation by-products and failing clear coat.

Once done wipe away any excess residue and follow through with a coating of clear coat spray to protect your headlights and there you have it.


In conclusion, automotive headlights changing pigment to yellow is a common problem affecting vehicles.

As a car owner, you can use UV protection all you want, but headlight turning to yellow is inevitable.

Although, you can prevent this by hiring a mobile car detailing professional to do a thorough polish of the lights.

The good news is that in comparison to other car features, yellow headlights may not pose a higher risk, but it is unwise to drive at night with a dim light.

Furthermore, the use of ceramic coating technology has been found to be very effective in slowing down the effects of oxidation, wear and tear for your headlights.

If of any interest, best to consult your Detailer for further information as results and grades can vary between brands.

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