It can be really frustrating if you see one headlight dim and the other bright. There could be a few reasons to take place this issue. But whatever the reason, it leads the appearance of the car to the worse.
Now the fact is, why is one headlight dim and the other bright? Can you solve it on your own without help from professionals? We will find it out through this article.
Possible Causes Why One Headlight Dim and the Other Bright
Despite this being a simple issue and easy to fix, this problem can take place for many reasons. The most common reasons are connection problems or blub issues. Let’s take a deep look to know why this happens.
1. Bulb Issues
One of the most common issues that can cause light brightness issues is the problem with blub. Normally, when a set of bulbs gets older it started to lose its brightness.
However, if you have faced this before and changed only one light then there is a huge possibility of occurring this again. This is totally usual. In addition, there is no guarantee that your new one won’t fuse.
So, if one headlight is dim and the other is bright, check your car blub first to ensure a problem with the bulb. And if the reason is with blub then simply change it.
2. Voltage Issues
When a car has a voltage issue due to wearing or battery problems light’s brightness can be different. Not only that if the voltage problem persists then it may damage the bulbs of cars.
Definitely, it can be a reason to misbalance the car’s light system which can give u a frustrating experience. And if get that the problem is with the lighting system then work fast to solve it. Otherwise, the voltage can hamper your car’s other electric system.
But the good thing is, this problem is very easy to fix. In most cases, it happens due to a faulty battery or loose connection which can be fixed by the owner itself. So don’t get panic if this happens to your car.
3. Faulty Wiring or Connections
It is very important to connect every electric system as much tight as you can. But there is so noob mechanic around us who doesn’t take it seriously. And that can cause wire burn, voltage problems which can lead to fuse lights, monitor problems, and much more.
So, if your headlight is not giving you balanced brightness then make sure your car’s cable wiring system is okay. Sometimes it happens for not connecting the wire well and sometimes it can be cut or damaged by other causes.
4. Failed or Dying Headlight Bulb
This usually happens for non-quality bulbs or, aged bulbs. When your car consists of a poor band bulb it can be dying very first. Though a new bulb can have problems with voltage or wiring-related issues but for the normal reason the problem is with the bulb itself.
That is why it is important to assemble a quality bulb for long-lasting brightness. If you are having problems like one headlight is dim and the other is bright then make sure the problem is with the bulb and if it is, then replace both bulbs with a quality one.
5. Damage to the Headlight Assembly
There are so many causes that can damage the headlight assembly. For example accidents, road hazards, not noticing speed breakers etc. For these types of causes, it is very simple to have a problem with headlight assembly.
Doesn’t matter what the cause is, you have to assemble your car’s headlight to balance your lighting system. To do so, it is better to go for a mechanic. And if you want to do it on your own, then you have to use your own brain to figure out the problem to solve it.
6. Faulty Headlight Control Module or Switch
This is very rare but still a possible reason for the dim headlights. This is not a problem that usually an owner can solve. So, if your battery, wiring system, the headlight is okay but one headlight is dim and the other is bright then the problem is maybe with the headlight control module or switch.
Here, if the problem is with the switch then you may solve it by replacing the switch. Otherwise, this issue can be solved by an expert mechanic. So if you have tried all the above-mentioned things and still having this issue, then it is time to take your car to an expert.
Related Article: Jeep Wrangler headlight switch problem
7. Other Possible Causes
Apart from the above-mentioned causes, there can be a few more causes like a faulty relay, poor grounding, and much more. These are very rare and can’t be solved by the owner themselves. So if you think that you can’t do this job then it is better to take help from a mechanic.
So, as you can see there are so many different causes that can make one headlight dim. Though for most cases it happens due to loose connection, wiring problems, and bulb problems but other causes can be reasons too. Here, if you are struggling to find out the exact reason then the next section may help you.
How to Diagnose the Problem
We already give you the hint in the previous paragraph. But if you missed it then read this section carefully. Let’s see step-by-step guidelines on how to diagnose the headlight dimming problem.
Step 1: Check the connection
Sometimes car light that is good in condition gives less brightness due to lose of connection. This is not good for a vehicle’s electric system. So the very first thing you have to make sure of is every wire connection is tight enough.
Step 2: Check the wiring
For the headline dining issue, the very first thing we recommended to do is to check the wiring. Sometimes cables that are connected to the light gets damaged due to the temperature of the engine or damaged by cockroaches or rat.
You may be wondering how cockroaches can damage wiring, sometimes cockroaches chew plastic wrap that covers the copper. So, you must check the wring before checking the light. Because opening the light is a bit tricky and needs effort.
Step 3: Look for battery health
If your car’s wiring is good then the second thing you have to look for is the battery. Here, if your battery voltage is okay then there are some other problems that may cause your car’s light misbalance. And if the battery’s voltage is below 11.5v then you may need to change the battery.
Related Article: Headlights not working after battery change
Step 4: Check the light
After basic checking, if you didn’t find any problem then maybe the problem is with the light itself. At this stage, you have to remove the light and check it using another power source if it is giving proper brightness or not. If there is a problem with the light then replacing is a simple solution. Otherwise, there are some other reasons.
Step 5: Look for professionals to help
When you get the field to find out the actual reason why is one headlight is dim and the other is bright, it’s time to take professional help. It is because there are some unusual problems that can fluctuate a car’s voltage that is a bit tricky and not easy to figure out. But don’t worry, professionals can easily handle this problem and fix it within a few hours.
We think these necessary steps are enough to diagnose the problem. But as a car’s warning system is a bit complicated, there can be so many different reasons for headlight dimming that a normal person might not solve. So, if one headlight is dim and the other is bright and you failed to diagnose the problem, then it is better to take help from a professional mechanic.
Frequently Asked Questions
1. What happens if you use the wrong Dimmer with LED lights?
If you use the wrong dimmer with LED lights, the lights may flicker, flash, or not turn on at all. It is important to use an exact dimmer that is compatible with your LED lights to ensure proper brightness.
2. Do all bulbs in parallel have the same brightness?
Normally, all bulbs in parallel must have the same brightness, as they are all receiving the same amount of electrical current. However, it also depends on the type of bulb you are using. If you use different types of aged bulbs in your parallel, then brightness may differ from one another.
3. How do you synchronize LED lights?
To synchronize LED lights, you have to use a controller that is specifically designed for this purpose. The controller will allow you to set the timing and sequence of the lights and create a coordinated lighting display.
4. Should you replace both low beams at once?
It is highly recommended to replace both low beams bulbs at the same time. It will ensure that the lighting is evenly balanced and that you have a consistent beam pattern.
5. Can you drive with one low beam out?
It is generally not safe to drive with one low beam out. Asit can reduce your visibility and make it more difficult for other drivers to see you. It is important to replace any burned-out bulbs as soon as possible to maintain proper lighting on your vehicle.
6. Which bulb is the brightest in parallel?
It actually depends on the type of bulb used in a circuit. As every bulb in a parallel gets the same electricity from the energy source, the bulb which is higher in volt or newer or good in condition will be the brightest.
7. How much does it cost to repair the headlight?
The cost to repair a headlight will depend on the specific issue that needs to be addressed and the cost of parts and labor in your area. In general, It costs around $20-$100 per light.
8. What happens if two bulbs of different wattages are connected in series?
In most cases, the low-watt bulb will give you less brightness. And if the watt of the lower-watt bulb is very low and connected to a high-volt power source then the bulb maybe burn out very soon.
9. Is it worth replacing the headlights?
Obviously, it is worth it! For a night or foggy travel, a headlight plays a vital role. In a low-light situation, if you drive with a less bright light then you may be putting yourself at a risk. So, if your car contains a dimmer bulb then replace it as soon as possible.
10. Do you have to replace bulbs with the same wattage?
It is generally recommended to replace bulbs with the same wattage as the original bulb to ensure that the new bulb is compatible with your vehicle’s electrical system. But if you need more brightness you can insert higher power light with advice from a professional. The professional will examine your car system to ensure that it is capable to run higher volt light smoothly.
11. How long should a headlight last?
The lifespan of a headlight can vary greatly. But on average a car bulb lasts over 5 years providing proper brightness. However, headlight bulbs can burn out or become dim at any time for various reasons. So it may be necessary to replace them at some point.
Final Verdict
Cars headlight works very well for the first 4-5 years without showing any problems. But if you are not a lucky one then your headlight can dim or even be damaged anytime. In most cases, hydrogen light gets dimmer faster than LED lights. So, if your vehicles have LED headlights then it is a plus.
So, why one headlight is dim and the other bright? We hope you get the answer through our article. If you have further queries related to this topic then feel free to comment below! Your valuable comment helps us to improve our service and assist you as well to know the accurate information.
Hello! My name is John Smith. I’m the creator of this website. Since childhood, I had a passion for cars and its mechanisms. So, I started working in the automotive industry when I just left school, and how I have over 10 years of experience in this industry. To make my experience alive through the content I started blogging through Lighting Sparkle. I hope that my experience through the content can help you a lot in making decisions and learning.