What Does A Headlight Assembly Include - Sunway Autoparts

What Does A Headlight Assembly Include: Parts Of A Headlight

Home What Does A Headlight Assembly Include: Parts Of A Headlight

Car lights are vital as they provide safety and security while driving. It seems inconceivable to drive long distances without them. Car lights can enhance the driving experience. Many car light options can be used to suit different purposes. That’s why every car light business needs to know aboutcar headlight parts names to serve their clients precisely with their needs. This helps business clients and builds a strong trust relationship between you and clients. Let’s check out everything about headlight assembly, including the different parts of the headlight.

What Is A Headlight Assembly?

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Headlight assembly, also called a headlamp or headlight in automobile vehicles, is a pair of lights attached to the car’s front. They illuminate the route ahead and assist the driver in seeing traffic. The headlamp is the connected device, and the beam of light from the headlamp is called the headlight. The most crucial component of a vehicle is the headlights. They allow the driver to drive in dark or night conditions safely. Headlights are essential for the driver’s safety and others on the road. Without them, the driver wouldn’t know where the vehicle is going. 

What Are The Parts Of A Headlight?

Headlamps are composed of a lightbulb and electric wires, which help carry the flow of charge to it, a reflective glass, and the shielding glass or plastic surface.

How To Replace A Headlight Assembly

Safety tip: When replacing any part of the vehicle, you should take proper preventive measures, like wearing latex gloves and closed-toe shoes,

Here are the simple tips to replace the headlight assembly

  • Find the headlight assembly by opening the hood
  • Make sure electrical connectors should be removed from the back end of the headlight assembly.
  • You can remove the headlight assembly by removing the retainer or headlight mounting screws.
  • Now, check for the damage in the headlight housing.
  • Remove the headlight housing that is damaged from the header panel.
  • Establish new headlight housings on the header panel. As needed, replace the destroyed mounting hardware
  • Headlight assembly to be installed in the housing.
  • Connect the wiring harness to headlight assembly.
  • Remove any components that were damaged to reach the headlight housing.
  • Next, Align the headlights.

Cost Estimation for Headlight Assembly Replacement

Without knowing the car’s make and model, the cost of replacing or repairing a headlight assembly can’t be accurately estimated. When estimating labor time for any vehicle, you should consider whether one or both of the headlight assemblies will need to be replaced. Also, take into consideration the type and ease with which the headlights can be removed. These factors will increase the labor time and the cost of a repair of headlight assembly.

Headlight Housing

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The headlight housing holds the bulbs inside the vehicle’s body to protect it from foreign particles. It can be either one or several pieces according to the vehicle model. Different colored lenses help distinguish between turn signal bulbs, parking lights, and headlights. Headlight housingshields the bulb from the engine bay and offers a reflective background to magnify and handle the light.

Types Of Headlight Housing

We can say the car’s headlight bulbs live in the headlight housing. It is simply the place that houses the car’s headlight bulbs. You should also know that each car’s headlight housing is different and can vary depending on the car’s model. Here are the three major types of Housing.

  • Reflector Headlight Housing 

Before 1985, nearly all vehicles used reflector housing for their headlights. It was the standard for most cars at that time. Dual filament bulbs are used in these housings. They are enclosed in a compartment-shaped bowl. The glass mirror in the bowl-shaped compartment reflects the light onto the road. Reflector headlights can also be known as sealed beam or directional headlights. In other words, if a bulb burns out, it can’t be replaced. Instead, the whole housing will have to be replaced.

You might wonder what to do to clean sealed headlights if they have become yellowed or oxidized. Modern reflectors have mirrors built into the housing, resulting from continuous improvement in technology. Mirrors direct the headlight beam so that there is no need to use a sealed bulb.

Although Reflector housings are generally more straightforward and less costly than other housing types due to their incapability to consolidate the headlight beam, they can’t do so as well as different housing types. This lack of light concentration can make it more difficult for oncoming traffic to see than other housing types.

  • H4 Conversions Headlight Housing 

The H4 conversion headlight system, a headlight upgrade for those who have reflector housing, is the best and most cost-effective option. The H4 conversion is a replacement H4 dual filament type bulb. This is different from reflector housing. The typical reflector housing uses halogen bulbs. However, the H4 conversion allows for the use of both HID and LED bulbs.

The H4 dual filament bulb can be removed from the H4 conversion housing headlight housing. This is another benefit. If one of the bulbs goes wrong, you don’t have to take the whole headlight housing apart and pull it out from the car. 

  • Projector Headlight Housing 

Headlights evolved with technological advances. In the 1980s, projector headlight housing was introduced. The projector housing was used only in luxury cars at the time. However, today projector housing is standard in all newer models of vehicles. Because of their focus properties, the projector housing permits the automotive headlights manufacturers to use effective bulbs like high-intensity discharge (HID), Halogen or LED (light-emitting diode). This makes it possible to avoid blinding other drivers.

The projector housing is different from the reflector housing. It has a headlight lens that functions as a magnifying mirror. The bulb is brightened by the cutoff shield that surrounds it. This shield helps to focus light in a more attractive and precise direction. This shield is what gives projector headlights their sharp cutoff.

Although reflector housings are still more common in vehicles than in the past, they are becoming more popular and can be found in many newer cars. Projector housings are more expensive than reflector housings due to their better ability to focus the light from the bulb. They make driving safer and more accessible for oncoming traffic. The beam created by the projector lens can be more even than that produced by reflector housings.

Headlight Bulbs


Headlight housing provides the home for headlight bulbs. Although the housings help distribute the light, the bulbs produce the actual light. Three main dimensions measure light bulbs: Lifespan, Kelvin, and Lumens.

Lumens, also known as the brightness or output of a light, measure its brightness. Kelvin (K) is the measurement of a bulb’s color temperature. The more the color temperature, the lighter or cooler-colored light will appear. Although it’s not as scientifically based, the expected life span of a light bulb is calculated in hours.

  • Halogen Headlights

A Halogen headlight bulb consists of a filament within an encircled bulb, closed and loaded with halogen gasses. The filament glows when it is turned on. The bulb’s halogen gas contains a lot of light intensifiers that help make the bulb bright enough for daytime visibility and night driving.

These bulbs are very simple and most cost-effective. Due to their simplicity, they are still the most commonly used bulbs on cars, but they are gradually being replaced by brighter, more efficient, and longer-lasting bulb types. They are the most common bulb type and are often used in conjunction with a projector or reflector housings.

  • High-Intensity Discharge or HID Headlights

These bulbs are ARC or Xenon bulbs and work slightly differently from halogen bulbs. Instead of a filament, these bulbs contain an electrode within a sealed bulb. The bulb comprises xenon gas, vaporized metals, and other materials that disperse light generated by electricity passing between the electrodes.

The typical HID headlights have a lumen rating of between 3000 to 5000 and are available in various color temperatures, ranging from around 4500 K up to 6000 K for vehicles on the road. These are safer than halogens at night and day and give them a cooler, more bluish appearance.

  • Light Emitting Diode or LED Headlights

LED lights are light-emitting bulbs. They have replaced halogen and HID bulbs to a certain extent. This is due to their effectiveness, durability, brightness, and design benefits over other bulbs. They work by passing electricity via a semiconductor or diode that emits photons. This method is known as electroluminescence.

  • Laser Headlights

Laser lights are the most potential headlights presently in the market. Laser lights are usually only available in high-end vehicles because they are expensive. They work by projecting a laser into a housing containing phosphorus. Laser lights can be more efficient and almost ten times brighter than LED lights; however, they are not widely used, and their cost is prohibitive. It is also difficult to mount them on vehicles. 

Headlight Bulbs vs. Headlight Housings

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When it comes to the headlights, people usually think about the regular bulbs for lights, not the housings that house the headlight bulbs. Headlight housings are what you see on the exterior of a vehicle, making the front part of the vehicle more stylish and appealing. They also disperse the light from the bulb.

Headlight bulbs and Headlight housing are the two main parts of the headlight assembly. Both headlight housings and headlight bulbs have their technology, but headlight bulbs carry the most technological weight because the headlight bulb is the main component of the assembly. The bulb creates light by carrying electric current via a filament that illuminates electrical resistance. The unit emits this light through specially-designed reflectors, which scatter it across the driver’s viewing area.

Headlight housing is the hard-plastic covering above the headlight bulbs and headlight rim that you can notice while looking at a vehicle from the front. Headlight housing protects the headlight bulb by residing it under the housing case. Both are interconnected and provide a more stylish appearance and convenience to the vehicle.

 Turn Signal Bulb 

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Safety is the primary concern for all drivers. Car manufacturers usually offer many internal and external safety features to improve the driving experience. But, unfortunately, the turn signal bulbs are one feature that is easy to overlook.

Turn signal bulbs are an essential safety device for communicating with other car drivers while driving. Usually, people fail to use the indicators, leading to an increase in accidents. 

Most vehicles have turn signal bulbs located on a small lever that attaches to the side column of the steering wheel. To activate the turn signal, pull the lever down. Pushing the lever up activates the signs on the left side for a right-hand turn. When you press the brake pedal, the brake lights will automatically turn on.

Four turn signal bulbs are used in vehicles: front left, front right, rear left, and rear right turn signal. These bulbs are usually located in the headlight or taillight system. Two additional turn signal lights are also available on newer vehicles: one for each side of the rearview mirrors. In many areas, it is mandatory to use restricted turn signal bulb colors, as in North Carolina, the front turn signal lights must be either amber or white, while the rear turn signals lights must also be amber or red. 

How to know if the turn signal bulb is dead?

Regular inspection of headlight bulbs is the best way to prevent dead turn signal bulb problems. It is easy to spot a burned-out signal light. You will first have to park the car in a safe place. Now, switch on the emergency lighting and circle the car to ensure all four main light bulbs work correctly. You should take note of dimming bulbs and replace them before they become a safety risk. Many vehicles also have a safety feature that can let you know when the bulb is dimming or dead. Some cars have a notification on the dashboard for when the bulb is low or dead. 

Headlight Lens

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The plastic portion of the car headlight covering the reflector and bulb is called the headlight lens. Dispersion optics headlight lenses are responsible for focusing, scattering, and deflecting the luminous flux collected from the reflector. Non-patterned ones have almost entirely superseded the standard concept of a cover lens with dispersion optics.

Headlight lens also comes with non-dispersion optics, also known as “Clear cover lenses” They lenses are only responsible for protecting the light from weather and soiling. These are used in the following headlamp systems.

  • Inner lens (DE System), for low beam, high-beam (bi-xenon), and fog light
  • A detached cover lens in the headlamp, just in front of the reflector
  • Headlamps that are completely free-form (FF) without any additional patterning

You can replace the vehicle’s headlight lens for many reasons. The most common reasons to replace the headlight lens on a car are discoloration from oxidation and damage. The most straightforward task in auto repair is to replace the headlight lens. It takes only a screwdriver. Choosing the right size lens for a vehicle is essential when replacing a headlight.

Material selection for cover lenses

Traditional headlight cover lenses are usually constructed from glass. These lenses must not contain streaks or bubbles. The cover lenses are now made from plastic (polycarbonate or PC) for the following reasons. 

This has many advantages over glass.

  • Extremely resistant to impact
  • Weightless
  • It is possible to produce smaller tolerances.
  • Offers more design space
  • This lens is scratch proof thanks to its special surface coating, following the SAE and ECE regulations.

Tips To Clean A Headlight Lens With Plastic Covers:

The following information is necessary to prevent damage to plastic lens cover lenses:

  • Avoid wiping off plastic lenses with a dry cloth. This can cause scratches.
  • Always read the instructions before adding chemicals to the water system for lens cleanings, such as antifreeze or cleaning agent.
  • Plastic cover lenses can be damaged by cleaning chemicals too harsh or not the right type.
  • Avoid using the prohibited high-wattage light bulbs!
  • Use only bulbs that have a UV-filter

Headlight Reflector 


The primary purpose of the reflector’s function is to capture as much luminous light radiated from the bulb as possible and direct it towards the road. Reflector optics headlights also have the light bulb filament at the base but use numerous mirrors to spread the light evenly. 

These headlights have the lens as a protective covering for the light bulb, mirrors, and reflectors. Due to their dome-shaped interior, reflector headlights can be easily identified. The reflector’s optics are designed to distribute light in the desired pattern. They can be customized to fit all specific vehicle brands and models.

Since the dawn of Automotive headlights, headlights reflectors have been a standard feature. When a light source (the headlight bulb) fills the cup of the mirrored housing, a reflector headlight is created. This creates a stream of light from the bowl directed in the direction of the light source. The simple yet effective design has stood the test of time and will continue to be helpful in our vehicles.

A headlight reflector has some drawbacks. The beam can’t be controlled. Omni-directional light sources are Omnidirectional and can be directed in all directions. The light bounces off the mirror surface. This creates a less distinct light source, which isn’t constant across the whole width of the output. This means that lights will lose brightness as they move away from the center.

Material selection for reflectors

Unlike reflectors made from sheet steel in years past, today’s headlamps are more demanding than ever. They must meet all requirements, including design, production tolerances, and weight. For reflectors, mainly plastics (various thermoplastics) are used. They are produced with high precision and reproducibility in mold making.

This permits the creation of multi-chamber and tiered systems. The reflectors are then coated to attain the desired surface quality. Reflectors made from aluminum or magnesium may be used in high-temperature headlamp systems. The reflector’s surface is vapor-plated with an aluminum reflective layer and a protective silicon layer.

Get Your Products From The Best Aftermarket Headlight Assembly Manufacturers 

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Aftermarket headlights have been growing in popularity among car owners who wish to improve the appearance of their car, increase their visibility at night, or replace old headlights. An aftermarket product is any product that doesn’t come from an original equipment manufacturer (OEM) but is compatible with it. A headlight is an aftermarket product.

A different company makes them from the car’s manufacturer. You may see them called replacement headlights. These products should not be confused with headlight bulbs. Every headlight needs three components: a lamp holder, lenses, or reflectors to do its job efficiently. These components don’t usually include bulbs because they are often replaced more frequently than other components. Why do car manufacturers, auto parts retailers, and people prefer aftermarket products over OEM? So here is some benefit that makes the customers choose aftermarket products.

  • Cost

Aftermarket parts are often cheaper than OEM parts. Generic parts for the car can help you save on repairs and bodywork. Insurance companies usually prefer aftermarket parts because they are more affordable and reliable than OEM parts.

  • Large Availability

Only the original manufacturer can sell original parts. It is possible to find parts because you cannot buy auto parts from any other seller. Sometimes you might need to travel a long distance to see the original parts.

You also have many sellers and manufacturers to select from in the local area. Generic parts are also easy to find, as OEM parts can be scarce and expensive.

  • Available immediately

It may take longer for the original parts to arrive than usual. You may have to wait until the OEM parts arrive to get them. Generic car parts are available immediately. You can place the order directly and have the part shipped to you much faster.

  • Qualitative

Original and generic automobile parts have different qualities. Aftermarket parts can replace the component that needs replacement. They are either equal or better than the OEM part.

One of the best things about Aftermarket parts is that they can be purchased at a higher cost to last longer than OEM parts. You can expect the same quality and performance as OEM parts.

  • Huge Variety

Even well-known companies only design a small number of genuine parts. Another benefit of using Aftermarket parts is that multiple companies can manufacture them.

There will be many different types of the same part. Because every company makes parts with different strengths and weaknesses, you have the option to select from many options so that you can find the right amount according to the needs.


Vehicle’s headlights are essential, not only for night vision but also to make the car visible to others. Each headlight bulb and headlight housing type has its pros and cons. Many types are upgradeable to give you the best lighting possible. At Sunway Auto Parts, stock a variety of headlight bulbs, Car Lights, Engine Parts, Body Parts and Accessories, Transmission Parts, Signal Light, Electric Parts, and Tools & General Parts for all makes and models. We offer genuine OEM replacements as well as premium aftermarket parts. 

Our car parts come with an industry-leading warranty and are rigorously tested. You can contact us for any related queries; we are available anytime to help you.

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