Oxidation Of The Lights
Oxidation is the most common cause of yellowing headlights. It mostly affects acrylic headlights upon exposure to ultra-violet rays. The lamp’s lenses usually come with a clear coat to prevent oxidation; however, it may wear over time and expose the plastic covering to these rays. Prolonged exposure to the beams will cause the lens to take a yellow hue, making the headlights foggy and affecting their lighting power.
Dirt
Is your headlight covering dark? If the answer is yes, then there is a huge probability that it is dirty. The darkening may come about due to the exhaust fumes from other vehicles, mud, and other debris present on the road. The good thing is that it is easy to deal with dirt, where a quick wash will do the trick.
Burnt-Out Bulbs
If the headlight appears dark, a probable cause may be burnt out bulbs. The bulbs wear over time, and they go dimmer until they finally give in. If you have a case of burnt-out bulbs, you have to make replacements for safe travel. This issue may be a pointer to other underlying problems, especially if it is consistent. Dimming lights maybe a sign of alternator problems, and you should check it.
Water Vapor
The headlight is usually airtight, and water cannot get in. However, with wear and tear, some water droplets may find their way into the bulb compartment as vapor; when the vapor settles, it forms water droplets, which, when combined with dirt, can make the lamp be yellow or have a brownish shade.
