Top 5 Reasons Headlights are Dimmer than they should be

We may get commissions for purchases made through links in this post. Thanks for the support! 👍

Surprisingly, headlights getting dimmer than they used to be is a major problem that actually happens to most cars as they age! This can be extremely dangerous with night driving, and even for visibility during the day, or in fog. This can be caused by a large amount of reasons, so we are going to help you out in discussing the major reasons why, and how you might be able to solve them for your vehicle.

So why may one of your headlights be dimmer than the other? Your headlights may be dimmer than the others due to them fogging (or clouding up) up primarily, however it could also be due to damage, malfunction, or just a simple bulb being improperly installed.

1. Foggy or Cloudy Lens

The headlights have a clear coat lens which allows maximum light passage. Over time the lens can oxidize as they are in direct contact with air and turn cloudy, which will deteriorate the lighting function of your headlights. A foggy lens can reduce light output by up to 70% if you don’t take care of it quickly..

When you note that one of your headlights is dimmer, you can remove the lens, clean the oxidized coating with something like this right here, and apply a new coating. If the problem has gotten to much due to pitting of the lense, the best solution is to replace the headlight assemblies all together..

It is important to note that some headlight models are more susceptible to oxidation than others. Also, it can depend on the angle, size, and materials used to craft the headlight.

If you leave your car in a garage for a prolonged period or leave it parked in the outdoor environment, your headlights can be affected. The damage can vary from a haze that causes dimmer light or complete opaqueness that will entirely block all light.

I actually had this happen on my 2003 Dodge Ram 1500, and you can read this article to see how I fixed it!

2. Old or Damaged Headlights

Depending on the type of your headlights and how you use your vehicle, the headlights will show major signs of deterioration after years of usage. The most affected part (outside of the exterior lens) is the bulb which is susceptible to frequent filament damage (causing the bulb to burn out), which will leave a metallic deposit on the capsule of the headlight.

The metallic deposits block out light and will dramatically lead to a dimmer headlight. Ensure you remove the headlights and check for any metallic deposits; in mild cases, you can clean the deposits and replace the entire headlight in severe cases.

3. Malfunctioned Ground Connection

Another major cause of a dimmer headlight is the poor ground connection to the headlight. If the connection is impaired, the headlight will not receive enough power, thus producing reduced light output.

Check the ground connection of your headlight or hire an expert to detect the problem.

This can also be noticed, as the headlights will likely flicker in and out as well!

4. Bulb Improperly Installed

Another major problem can be that one of your headlights is improperly installed.

It can be due to the bulb is not fitted properly in the headlight socket, and the headlight is not accurately projecting light. If such a malfunction occurs, the headlight will look dimmer than the other one.

After an accident, your headlight can be misaligned due to the force of the impact causing the frame to point the light in a different direction.

This results in a misaligned headlight assembly which causes the beam of the light to point much lower.

If one of your headlights is affected, it will appear dimmer than the other one.

5. Headlight Connector is Impaired

The manufacturer of the vehicle may have installed a poorly functioning headlight connector. In this case, we highly recommend replacing the wiring harness for the headlight with a new connector. This should solve this problem for yah!

If you don’t pay attention, the impaired wiring system can cause the melting of the plastic connector. In such a case, there will be poor conductivity of power in the headlights, thus resulting in one of the headlights being dimmer.

How to Keep your Headlights Bright

  1. Examine your headlights regularly to avoid any oxidation or clogging of the lens
  2. If your lens is clear but the headlight is still dimmer, you might require a new headlight installation. You can get a new set here, as I have done that myself with my truck!
  3. Ensure you clean your lens regularly using a good household glass cleaner. Cleaning will ensure your lens are clear and will make your headlights produce bright light.

Frequently Asked Questions

How can I make my headlights brighter?

The easiest way to make your headlights brighter, is to get a brighter bulb, mainly by switching to LED. Keep in mind though, there are laws around this, as these bulbs can blind oncoming traffic, and cause an incident.

Why did my headlight burn out?

There are two primary reasons your headlight likely has burned out. The first is that it has just reached its lifespan, and it is time for a normal maintenance item. The other may be that there is moisture on the inside of your headlight housing, which you will want to remove ASAP, or you can replace the housing as well.


Properly functioning and bright headlights are quite handy in any vehicle; they guarantee the safety of your car, especially at night. When purchasing new headlights for your car, ensure fancy options do not sway you; functionality and brightness of the headlights should be your number one priority.

Also, ensure proper alignment in a vertical position to properly illuminate the road and minimize glare to other incoming drivers.