House Grail is reader-supported. When you buy via links on our site, we may earn an affiliate commission at no cost to you. Learn more.

Why Are My Headlights So Dim? 5 Possible Reasons

Car headlights

Nighttime driving is more dangerous than daytime driving. Fewer than half as many cars are on the road, but 40% of accidents occur at night. Your vision is significantly impaired, even with streetlights and ambient lighting, and you have to rely on your headlights to provide adequate illumination.

If you notice that your headlights are emitting less light, there are several possible causes. Some have simple remedies. Others require more work at a greater cost. Before you can repair them, you need to identify the cause. Below are five possible reasons for dimmed headlights, along with information on what can be done to fix the problem.

car and road divider

The 5 Reasons Why Your Headlights Are So Dim

1. Blown Headlight Bulbs

Credit: dietmaha, Pixabay

The most obvious cause of dimmed headlights is that the bulbs have blown or are dying. Some bulbs will only last about 1,000 hours, so if you regularly drive at night or have your headlights on during the day, it won’t take too many years for one to blow.

As a bulb nears the end of its life, it can start to dim. If you notice that one side of the road in front of you appears darker than usual, it could be the cause. Most cars do have sidelights as well as main headlights. If the main headlight blows, you will be left with low lighting.

What to Do About It

Pull over safely, turn your headlights on, and get out of the car to see whether your headlights are dim or blown. It is possible to change your headlight bulbs. In most cars, you can replace the bulb by opening the hood, unfastening the casing, and changing the light.

However, some cars require that you access the bulb through a wheel arch or by removing windscreen washer bottles. If you don’t want to change your bulb, a mechanic can do it.

2. Cloudy Headlight Lenses

It may not be the bulb causing a loss of illumination. The lens is the transparent cover that protects the bulb while allowing light out. Over time, the acrylic can become discolored or clouded, especially when exposed to UV rays from the sun.

When you look at the lens, if it has a yellow discoloration or appears cloudy or foggy, oxidation is the likely cause.

What to Do About It

Headlight lenses can be restored, or they can be replaced. Restoration usually costs less than replacement, but if your lens is damaged or badly worn, it could be time to invest in a new one.

3. Electrical Problems

car headlight repair
Image Credit: DiPres, Shutterstock

Headlights draw power from the battery of the car. A variety of electrical problems could cause headlights to dim. The wiring could have come loose, a fuse may have blown, or you may have another component leeching power from the battery, causing your lights to dim.

What to Do About It

Whatever the cause of the electrical problem, a mechanic can help you identify the cause and fix it. Alternatively, you can replace a blown fuse yourself, and if the problem is a worn battery, you will likely have noticed other electrical problems with your car. The internal lights will dim, and you may find it takes longer to start the car in the first place. Try boosting or charging the battery to determine whether this is the cause.

4. Incandescent Headlight Bulbs

Incandescent light bulbs are similar to the old lightbulbs used in homes. Some consist of a wire filament inside a glass bulb. The headlight uses mirrors to direct the light forward. Although they have been used as the primary type of headlight for many years, most modern car manufacturers use alternative bulb types. For example, LED lights are increasingly used in modern cars.

If you notice that your lights are dimmer than those of other cars, it doesn’t necessarily mean that yours have dimmed or are failing. It could be that they are incandescent.

What to Do About It

If you have incandescent bulbs and want brighter lights, consider having them replaced with LED or another type of headlight bulb. The replacement is simple, and if you don’t want to do it yourself, a professional mechanic can help.

5. Inadequate Headlight Brightness Setting

projector headlight
Image Credit: BLKstudio, Shutterstock

Many cars provide a way of altering a car’s headlight settings. Some have basic settings that allow you to aim the light beam higher or lower. At the lowest setting, the headlights will illuminate the road directly in front of you, while a higher setting will light up more of the surrounding and approaching areas. More advanced features also allow you to increase or decrease the brightness of the headlights.

What to Do About It

Check your owner’s manual for headlight settings and determine how to increase the brightness or raise the height of the and road divider


Headlights are a vital part of your car and are critical for safe nighttime driving. If you have dimmed lights, check the bulbs and the lenses are clean and in good condition, and ensure that your battery and wiring are in working order. Check for headlight brightness settings for a potentially easy fix. Alternatively, upgrade from old incandescent bulbs to LED or LID bulbs.



Featured Image Credit: Pexels, Pixabay


Related posts

OUR categories

Project ideas

Hand & power tools