HID Headlight Conversion Kits FAQ

HID Headlight Conversion Kit FAQ

Short for High-Intensity Discharge, HID lights are one of the most popular, and brightest, alternatives to standard vehicle headlights. The best way to understand why HID headlights are unique is to compare them with the other headlight options. Here’s a rundown:

What Are HID Headlights?


Halogen bulbs are the most common type of headlights. They’re standard issue for most cars and trucks.

Halogen bulbs use a tungsten filament, which glows when electricity passes through it. It’s the same basic type of bulb as the ones found in your home.

Aside from light, halogen bulbs also produce heat. Plus, while they’re bright enough for standard night driving, they’re the dimmest type of headlights. They’re not ideal for heavy rains or fog.

LED Lights

These headlights are powered by light emitting diodes, which is where the term LED originated. An LED is a tiny, glowing electric circuit. These diodes are small and relatively weak on their own, but when mounted in a cluster, they produce a bright light.

(Looking for LED lights? Check out our review round-up and complete guide.)

HID Lights

HID is short for high-intensity discharge. They’re also referred to as Xenon bulbs or Xenon HID bulbs. You’ve almost certainly seen these bulbs on the road before. They’re known for producing a bright, intense white light.

Instead of the tungsten filament found in halogen bulbs, Xenon bulbs have no filament at all. Instead, they illuminate using a combination of an electrical charge and xenon gas.

Xenon bulbs are graded in two ways:

  • Temperature
  • Lumens

The bulb’s temperature refers to the color it produces. Although the white Xenon bulb is the most common, the color spectrum varies significantly from dim yellows to vibrant blues, purples, and more. The flexible color options are a major reason for the popularity of HID headlights.

Temperature is the color shade; lumen output is the brightness level of the color. The higher a bulb’s temperature, the lower the lumen output required.

Headlights are typically measured in Kelvins, a temperature measurement scale used internationally. Most HID headlights fall within the range of 3000K to 12000K.

How Do I Install HID Xenon Headlights?

First, you’ll want to gather up all the necessary tools. You’ll need:

  • HID Conversion Kit (Check out our list to find the best options)
  • Crescent Wrench
  • Lightweight cloth gloves
  • Rubbing alcohol

As you can see, not much gear is required. Once you’ve gathered up everything you need, you’re ready to install the headlights.

Step 1: Park Your Car

Turn off the engine and allow the car to cool. Prop open the hood.

Step 2: Disconnect the Battery

Disconnecting your car’s battery protects components from damage and yourself from accidental injury.

Use the crescent wrench to loosen the nut on the negative terminal. Then remove the negative battery cable. Wrap the end in masking tape to prevent accidental reconnection.

Remove the positive battery cable using the same technique. Depending on the type of kit you’re using, you might later connect the positive lead to the wiring harness of the headlights—but that’s later on. For now, set the positive cable aside.

Step 3: Remove the Halogen Bulbs

Depending on the type of vehicle you have, your headlights will either be uncovered or behind a housing. Removing the housing usually just involves unscrewing a few screws.

Before you remove the bulb, remove the stock harness. It should pull out with a slight click.

A quick note about bulb glass and your fingers:

Never touch a halogen or HID bulb with your bare hands. Oils and fats from your fingers easily stick to the unique quartz-type halogen glass. Touching it results in weak spots, a shorter lifespan, and uneven heating.

Most people wear either cotton or disposable gloves. Cotton gloves are usually a little more comfortable and allow precise movement. However, any type of glove which prevents your skin from touching the glass will be fine.

Don’t worry if you accidentally touch the bulb! It doesn’t permanently ruin it. Clean the bulb with rubbing alcohol and a clean cloth or Q-Tip.

Step 4: Install the Xenon Bulbs

The bulbs will likely be packaged inside a plastic shell. Take them out. Of course, you still need to be careful to avoid touching the glass. It’s far more important to avoid touching the new bulbs than the old ones.

Press the HID bulb into the headlight housing.

Step 5: Connect the HID Ballast

Connect the HID ballast to the stock socket. You’ll hear a click when it’s secure.

Step 6: Reconnect the Battery

Reverse the earlier steps to reconnect the battery safely.

Step 7: Test the Headlights

They’ll either work… or they won’t. If they don’t work right away, hang tight. There’s a simple solution.

Locate where the extension/adapter wire connects to the ballast. Turn that wire 180 degrees. Flipping the adapter should turn the headlights on.

There’s nothing wrong with the ballast. Flipping is sometimes necessary to make the wires in the ballast line up correctly with the vehicle’s electrical system.

Step 8: Mount the Ballast

Once the ballast is in the correct position, you’ll want to mount it in the car. Some kits include elaborate mounting systems. While they’re more involved to set up, they do keep the wires and ballast securely in place.

Others are more low-tech. You mount the ballast with either zip ties or double-sided tape. Even these low-tech methods are usually good enough for normal driving.

Mounting the ballast is one of the most important, as well as one of the more confusing, aspects of the installation. Here’s a closer look at the two mounting options:

Mounting System

Most mounting systems include brackets, nuts, and bolts. You have two placement options. You can attach the brackets to your vehicle’s frame using existing holes, or you can drill new ones.

Depending on the make and model of your vehicle, pre-drilled holes might be available. You might even have factory-installed brackets for your existing headlights.

Drilling holes into your vehicle’s frame is another option. Many people are reluctant to do so, for fear of causing damage. Before drilling, make sure you understand how the frame will be affected.

Zip Ties

Zip ties are another option. Although they seem a bit low-tech, they’re often the better choice.

Fourteen-inch zip ties are a popular choice, but similar sizes will probably work well, too. Place four ties vertically across the ballast and four horizontally. Then weave the ties together, in the same way you’d weave a basket. Cinch the ties as tight as possible.

The basket is often far easier to attach to your frame. You can use additional ties to attach the weave to the frame or any out-of-the-way location under the hood. Just make sure it avoids any belts or other moving parts.

How Do I Select HID Headlights?

There’s no one absolute best type of conversion kit. Instead, you’ll want to find the kit which fits your driving style, design preferences, and typical driving conditions. Here are the main features to consider when selecting a kit:


Xenon lights are typically associated with a bright, white color. But a wide range of color options is also available.

The color of the light is measured in Kelvins. You’ll find kits available between 3000K to 20000K, although the ideal range for driving is between 4300K to 6000K.

The two most popular colors are:

  • 6000K – This is the famous bright white.
  • 8000K – These headlights are a bright blue often called “iceberg blue.”

Generally, the lower the Kelvin, the more yellow the light. As Kelvins increase, the light becomes a deeper blue. However, a high Kelvin number doesn’t directly correlate to brightness.

4300K is almost identical in brightness to natural sunlight. Although it lacks the cool factor of brighter lights, 4300K dramatically increases visibility when driving at night compared to halogen bulbs and even other HID bulbs.

Increasing the Kelvins beyond 4300K doesn’t necessarily increase visibility. Around 6000K, everything in the light starts to look pretty blue. Finer details can blur together. (A 6000K light is 95% white and 5% blue.)

Around 10000K, the light is so blue projection becomes basically non-existent. Lights this highly saturated are used for cosmetic purposes only and are unsafe for nighttime driving.
3000K is usually about as low as most headlights go. At that level, the light is often used as a substitute for fog lights. They’re not especially better, visibility-wise, than Halogen fog lights, but they are more energy efficient.


The kit should include a ballast for every bulb. Most kits have two of each. The ballasts must be made for automotive HID lighting systems. You want to see that language specifically, as HID lighting systems also exist for other purposes.

Also, check how the lights are packaged. Each light should be contained in a plastic vial. A secure storage container helps ensure the light is free from defects or damage.

Customer Service

Calling or emailing a company about a light bulb might seem a bit silly, but accessible customer support can be a real lifesaver if you run into a problem. Live support is ideal for help during installation. Email support isn’t quite as good as talking to a live agent, but it can help you with on-going troubleshooting.

How Do I Test Headlight Brightness?

Each state has unique laws and regulations regarding headlight brightness. Federal standards also apply. In the 1960s, federal regulations required all headlights to be exactly the same. However, the rule was lifted in 1983.

Today, a wide variety of headlights are allowed. Check your state regulations for specifics regarding the maximum and minimum allowed brightness.

Most states require headlights illuminate at least 115 feet. Most Xenon lights, even those well under 4300K, should reach that distance without a problem. However, after installing new lights, consider measuring the brightness.

A digital light meter is the most accurate way to measure. Take your car to a dark area away from as much artificial light as possible. Point the headlights at the meter for an instant reading.

You can also go old school. Place an object 115 feet in an empty parking lot. Sit in the driver’s seat, turn on your headlights, and see if you can see the object.

Always test your new lights in safe conditions away from traffic. Make sure they’re bright enough to maintain proper visibility.

What Are Bi-Xenon Headlights?

Traditional HID bulbs only replace the low beams. For most cars, this means the high beams will continue to be powered by halogen bulbs.

Of course, increased visibility is a major benefit of HID beams. If your HID low beams are just as powerful as your halogen high beams, then what’s the point of the high beams?

Bi-Xenon headlights generate both HID high and low beams. In some cases, the high beam needs a second or two to warm up initially. But then you’ll be able to switch between the two instantly.

What Are The Benefits of HID Headlights?

HID headlights are popular for a few reasons:

  • Increased energy efficiency
  • Increased brightness
  • Style

Increased Energy Efficiency

When they’re first turned on, HID headlights require a rather significant burst of electrical power, more than a halogen or LED bulb. But once they’re on, HID headlights only need a small amount of energy to maintain brightness.

HID headlights are the most energy-efficient option. They require roughly half the energy of a standard halogen bulb. Plus, they last much longer than halogens.

Increased Brightness

When comparing brightness levels between halogen and HID, the results aren’t even close. HID bulbs are significantly brighter than halogen ones. Typically, HID bulbs increase brightness by a multiple of three to five.

Additionally, HID bulbs illuminate more of the landscape. The design and brightness of the bulbs create a broad field of vision, including increased peripheral vision. Plus, the white light is clearer and sharper than the dull, yellow light from halogen bulbs.

Increase brightness leads directly to increased safety behind the wheel. You’ll have an easier time spotting people, obstacles, hazards, and more. HID is the far better option when driving at night during bad weather, in areas without streetlights or other extremely dark conditions.


Many people simply like the HID style. The bright, white beams do help your car stand out on the road. Plus, HID lights are featured in tons of popular movies, including the Fast & Furious franchise.

Let’s face it: many car accessories are selected mainly because they look cool. While the increased brightness and energy efficiency are certainly pluses, you don’t need a reason to install HID lights aside from liking the way they look.

What are the Downsides?

Before installing new headlights, consider these potential drawbacks:

HID bulbs are more expensive than halogen bulbs. Because Xenon bulbs last at least three times as long as halogen, they’re the more economical option over time. But they do cost more initially.

Also, they cost more to replace if broken.

Additionally, xenon bulbs can blind other drivers. Truthfully, these bright bulbs don’t always have the best reputation on the road. When improperly installed, HID headlights can easily point directly into the windshields of oncoming traffic. That’s why proper installation is so important.

Finally, they’re not great in fog. The unique light reflects off the fog into the driver’s face easily. It can be pretty dangerous when driving in thick fog, especially with bright HID headlights.

However, 3000K HID lights can be an exception. In some cases, they’re used to replace factory fog lights. Their effectiveness will vary based on the conditions in your area. In some places, like the Pacific Northwest, halogen fog lights are the safest option.

What’s It Like Driving with These Headlights?

If you’ve never seen these headlights from the driver’s seat, you’re probably going to be surprised at how different they are from halogens. They’re not “halogens but brighter.” Instead, they create an entirely new way of looking at the road.

Halogen headlights, like the lights which are probably in your house, fade away with distance. You can’t see a precise moment where the light stops.

Xenon lights work differently. They stop, rather cleanly, at a certain range. The effect on your eye can feel disorientating, especially when driving at high speeds.

Can I Install These Headlights Myself?

Absolutely! Swapping out your factory headlights for Xenons is a fairly simple project. Most D.I.Y. mechanics should have no problem. Installation typically takes 15 to 20 minutes per headlight.

However, if you’re not comfortable installing the lights yourself, practically any local mechanic will be able to install them for you. If you purchase the lights separately, installation costs should be minimal.

The trickiest aspect with installation is aiming the headlights in the right direction. Even a minor misalignment can result in your lights shining right into the faces of other drivers.

How Do They Work?

Before we start the installation process, let’s take a quick look at what the different components are and how they fit together.

The HID Bulb fits behind the front lens. It provides the light. The bulb fits into the stock harness, which is the same connection the regular halogen bulb uses. However, with HID lights, the harness plugs into a new component, an adaptor/extension wire. Finally, the wire plugs into the ballast.

What is a Ballast?

A ballast is probably the single most important part of the headlight kit – even more important than the bulb itself! If any problems occur with your HID lights, the ballast will be one of the first items to troubleshoot. Understanding how the ballast works and where its located can help prevent headlight headaches down the road.

Ballasts have existed for decades. They’re a crucial component in fluorescent light but have recently grown in popularity because they’re needed in High-Intensity Discharge lights, too.

The ballast has two functions:

  • It provides energy to start the light
  • It steadies the power supply

When the headlights are turned on, the ballast sends a surge of electricity from the car to the headlight. By creating an arc between two electrodes, the bulb lights up.

Once the electrical arc is established, the ballast performs a second function. It reduces the voltage then regulates the electric current, keeping the light steady and free from flickers.

If the ballast isn’t working properly, the headlight will draw power too quickly. The headlight can burn out within minutes. The effects of a broken ballast can resemble a blown-out bulb. If a headlight seems to be constantly blown-out, even after replacing it with a new bulb, check the ballast.

How Are HID Ballasts Different than Traditional Ones?

HID ballasts have a few different features than the ones found in fluorescent lights. First, they’re fast acting. After all, your headlights can’t warm up. They have to provide instant illumination.

The lights also need to be able to turn on and off as quickly as needed. With halogen lights, this isn’t an issue. However, it becomes more complicated with Xenon gas.

The gas needs to cool down before the current can be administered. HID ballasts use special circuitry to regulate the gas allowing it to turn on and off without any delays.

Finally, the ballast converts DC to AC. HID bulbs require AC, but most in-car power systems create DC.

Never use HID headlights with a non-HID ballast. Doing so will almost certainly damage the bulb and possibly your entire lighting system.

Ballast Location

Each HID light uses its own ballast. Most conversion kits include two ballasts. They’re thin, rugged rectangles which attach to the adaptor wire.

Ballasts are often secured inside an included mount. Typically, the mount is placed near the back of the headlight. (The best way to mount a ballast is covered in the Installation section below.)

Factory-fitted HID ballasts are different than the ones found in kits. Factory ballasts often connect directly to the bulb or are otherwise installed permanently into the car. If your car has stock HID lights, the ballast can sometimes be difficult to access.

Brett Gordon

The engine behind editing at DigMyRide and the brains behind its build. During the day, Brett is a thirty-something dude from SoCal climbing the corporate ladder, but by night, he spends his time contributing to the online world of automotive tech & trends.