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How to replace headlight assembly

Headlight assembly is a crucial part of your car in ensuring driving safety in the dark. 

However, at certain points, for some reason, it needs replacing and you may think of taking your car to an auto body service shop. 

But, that’s actually unnecessary as replacing a headlight assembly in your vehicle is a quite simple process and you could be your own mechanic. 

In this article, I will give you some guide on how to replace the headlight assembly yourself.

How to replace headlight assembly


What are auto headlights?

How to replace headlight assembly


Car headlights are a lighting device which is an indispensable part of cars when operating in the dark. 

The headlights create a strong beam of light capable of illuminating about 100m or more and focusing on the road surface. 

Not only that, headlights are also considered a highlight to help create a unique style for each vehicle.


How many kinds of auto headlights are there?


Currently, on the market, there are 4 types of headlights most commonly used in cars:

+ Halogen lamp: This is the most commonly used headlight type today for the advantage of low cost and long life. However, this type of highlight has a disadvantage that concerns drivers. It consumes too much energy.

How to replace headlight assembly

+ Xenon-HID: Born in 1991, Xenon-HID is a high-intensity lighting system that improves driver visibility. The downside of this product is its high cost.

How to replace headlight assembly

+ LED: This type of headlight is well received for its high aesthetics, fast lighting-up and energy-saving feature. Yet, just like the Xenon-HID, it’s not a cheap product.

How to replace headlight assembly

+ Laser: This is the most modern and expensive lamp today. This lamp does not have a phase mode, so it is necessary to install additional Bi-Xenon lights or LED lights.

How to replace headlight assembly


Causes of car headlights damage

How to replace headlight assembly


It’s usually said that if you want to cure a disease, you’ll need to know its origin. It’s the same here. 

If you want to know how to replace a headlight assembly, you should get the hang of what has caused you to do that. 

Based on what we have researched and experienced, there are five common causes leading to the damage of car headlights.

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+ The light bulb goes out

Each bulb usually has an average life of about 500 – 2,000 hours of night driving. Car bulbs should be replaced after 5 years of use. If you often operate at night, you should pay attention to replacing the light bulb.

+ The headlight fuse is burned

The fuse is designed to “burn out” if the vehicle is overcharged. 

Often the headlight fuse can blow out due to the operation at improper wattage of the bulb or a short circuit. If the fuse fails, replace it quickly.

+ The headlight relay switch is faulty

The relay switch adopts one or more relays to control the bulb. 

If the headlights don’t work then the problem may lie in a faulty relay switch. It is recommended to replace the relay for the headlights to fire back to normal.

+ The power cord is faulty or damaged

Sometimes the power cord may be broken, corroded, poorly connected or damaged. 

This will make the wires unable to efficiently transfer electrical energy to the headlights causing flickering.

+ The generator isn’t working

When cars use Xenon headlights, if the alternator fails the bulb will not light. 

Because with this type of headlight to bring xenon and salt to the plasma state, the HID generator must increase the voltage up to 30,000V, then stabilize about 90V when the bulb operates.

+ Headlight on switch is broken

For cars that often operate at night, turning the switch on and off many times will wear it out or make it become lazy. 

Therefore, it should be checked periodically to avoid these conditions from happening.


Tools for replacing a headlight assembly


Tools needed to replace a headlight assembly vary, depending on what type of car you have. But, in general, you’ll need:

+ Screwdrivers

How to replace headlight assembly

+ Ratchet, appropriate size sockets and wrenches

How to replace headlight assembly

+ Safety glasses

How to replace headlight assembly


How to replace a headlight assembly


Now we get to the fun part: headlight assembly replacement. 

Are you ready to grab some tools and get dirty? Good. We’re going to discuss how to replace a composite headlight assembly that uses a halogen headlight bulb.

Before we start, however, keep in mind that all vehicles are different. 

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Be sure to follow the repair information for your specific application. Repair manuals, such as those from Chilton, are useful, but an ALLDATA subscription is even better. 

ALLDATA has single-vehicle subscriptions for DIYers that provide detailed factory repair information.

Now, to remove a headlight assembly on your own, you can follow 13 following steps:

1. Put on your safety glasses.

2. Make sure the vehicle’s ignition, as well as the headlights, is off.

3. If necessary, remove the front bumper cover or grille by following the factory repair information.

For some (but not all) vehicles, this must be done to access the headlight assembly retaining fasteners. 

The process generally involves removing a collection of screws and/or clips to free the bumper or grille.

4. Once you have direct access to the headlight assembly, remove the bolts or screws holding it in place.

5. Pull the headlight assembly out and away from the vehicle.

At this point you should keep in mind that there may still be retainer clips holding the assembly in place. 

You’ll need to carefully dislodge the assembly from the clips as you pull it toward you.

6. Disconnect the electrical connectors from the back of the assembly.

7. Some replacement headlight assemblies will come with new bulbs.

If yours do not, you will need to remove the old bulbs and sockets so they can be reused. 

Typically, this involves turning the bulb or its socket counterclockwise to remove it from the headlight assembly. 

There may be a retainer you need to remove first before the bulb can be rotated and removed.

8. Compare the new headlight assembly to the old headlight assembly to be sure both are of the same design.

9. Reinstall the bulbs and sockets in the headlight assembly as needed.

10. Reconnect the electrical connectors.

11. Mount the headlight assembly in place. Be sure that it slides into any retainer clips affixed to the front of the vehicle.

12. Reinstall the headlight assembly mounting bolts and carefully tighten them down until they’re snug.

Do not overtighten. If needed, you can consult the factory repair information and use a torque wrench to tighten the fasteners to manufacturer specifications.

13. Reinstall the front bumper or grille as needed.

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That’s the end of our comprehensive guide on how to replace a headlight assembly. 

We hope that this article would be a useful assistant to you if you’re struggling with your headlights. 

As a final remark, we would like to say that you should check on your headlights frequently and stop procrastinating fixing or replacing them when they are faint or dead. Just like your seat belt, they’ll keep you safe when you’re out for a drive in the dark.




How much does it cost to replace a headlight assembly?


It depends on the extent you’ll have to replace your headlight assembly. 

For example, on average if you only need to replace your halogen bulb in your headlight assembly, you will have to spend somewhere between $65 and $70, including the labor cost and the cost of a new bulb. 

The amount of money would increase up to $100 or more if a high-intensity discharge bulb replacement is needed. 

And in the worst scenario, if you had to get your entire headlight assembly replaced, you might have to spend from $250 to $700. 

Of course, if you could do the replacement work on your own, the cost would be much lower.


How long does it take to change a headlight assembly?


Although changing a headlight seems to be a simple task and you can do it yourself, it’s a pretty lengthy process after all. 

You will have to spend at least two hours to change the headlight on average. 

So before getting down to the business, make sure that you have plenty of free time and that you are patient with the work.


Can you drive with one headlight?


Driving with headlights on is legally regulated in most states of America. 

In general, you must turn your headlights on when you drive from sunset to sunrise to ensure your own safety and others’. 

And in most states, it’s also the rule that you have to drive with two headlights on unless you’re riding on a motorcycle. 

So you should learn the law to know that driving with one headlight is allowed or not.

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