CAR ID
Time for reading: 7 min.

How To Install A Set Of Custom Headlamp Assemblies

Custom headlamp assemblies give your vehicle new "eyes". We cover the installation process – including bumper cover removal, transferring bulbs, wiring harnesses, and aiming.

If the front of your vehicle is its "face", then the headlamps have long been considered the vehicle's "eyes". Everyone notices them. One of the most distinctive changes you can make to the face of your car or truck is to replace the factory headlamp assemblies with a custom set. Your ride will take on a personality all its own, and will gain a distinctive appearance that will set it apart from all the other look-alike vehicles on the road.

Our custom headlamps are sold in pairs, designed to fit in the exact location of your factory units, and cost less than you might think. In the scope of this article, we'll review the step-by-step basics of installing complete custom headlight units designed for your specific vehicle. Because xenon headlamp assemblies require extra high-voltage equipment and control modules, we've left them out.

Before You Begin

For any new part, headlights or otherwise, it's always a "best practice" to start by unpacking the components and verifying that everything is in good shape. For your new headlamp assemblies, remove them from the box and ensure that there is no physical damage.

If your headlights have single wires for DRL or halo lights, touch these wires (red or white are usually positive, and black is usually negative) to a 12 volt source such as the car battery to ensure that all lights function.

Make sure that everything you ordered is included, and if the light manufacturer included their own installation instructions, use them along with this guide.

Removing & Installing Bumper Covers (If Required)

Tools needed: open-end wrenches, socket wrenches, rivet gun (on certain vehicle applications), screwdriver(s), Torx head bits (if applicable), electric drill (if applicable)

This is often the first step because many modern vehicles require the plastic front bumper cover to be slid loose an inch, or completely removed in order to access the anchor points where headlight assemblies bolt on. If you're not sure whether this step is needed, we recommend checking with your vehicle manufacturer or accessing a repair manual online. Removing and re-installing the front bumper cover is relatively easy because most are designed to unbolt and slide off with basic hand tools.

Taking a close look at the bumper cover, you'll notice that the bolts which secure it in place are typically exposed once you open the hood. They can also be found underneath the vehicle where the bumper cover meets splash shields, and near the edge of wheel well openings where wheel well liners meet fenders. There may also be small plastic caps or clips covering such bolts, so remove them with a small flathead screwdriver.

Typical Locations Of Bolts And Hold-Down Clips
Typical locations of bolts and hold-down clips that secure a front bumper cover.
Bumper Cover
Many bumper covers are designed to slide horizontally along special brackets before detaching.

Remove the bolts themselves with an applicable socket wrench or flat wrench. In the event your vehicle manufacturer has used rivets to secure things (wheel well areas), they'll need to be drilled out with a traditional drill. Then you'll need a rivet gun to reinstall new ones - not an expensive purchase, but the proper tool to use. When drilling out rivets, bits designed for drilling into metal are most suitable due to a higher heat rating.

Once all fasteners are removed, the bumper cover can be detached. Many are designed to slide horizontally along special bracket pieces mounted underneath before coming completely loose, so move the bumper cover in this fashion first if you aren't able to obtain specific instructions on your make and model.

Unbolting Your Old Headlamp Assembly

Tools Needed: Socket wrench, screwdriver(s)

Removal Of Front Grille Section
Removal of front grille sections to access headlamp anchor points is required on many vehicles.
Example Of Location Of The Anchor Bolts
An example of where anchor bolts for many styles of headlamp assemblies may be located.

Depending upon the year and model of your car, you may need to remove your vehicle's front grille section in order to access bolts or clips that secure the headlight assembly in place. This can be done by removing the screws from the top or sides of the grille and/or by releasing hold-down clips found on some vehicles with a flathead screwdriver.

Loosening Of Anchor Bolts Of Headlights Assembly
Examples of loosening headlamp assembly anchor bolts.
Headlamp Assembly Anchor Bolts Loosening Process

Once any grille, trim, and bumper cover sections have been removed in order to provide access to headlamp assembly attachment points, you can proceed with unbolting them - usually a small socket wrench serves best for such applications. Look for hold-down bolts in the metal body panels above and to the side of your headlamp assemblies. Some vehicles also feature hold-down clips on the headlamp assembly which can be released with a flathead screwdriver.

Hold Down Clips Released
An example of hold-down clips that must be released before a headlamp assembly can be removed.
Headlamp Slide Away
After all applicable hold-down bolts and clips have been removed, old headlamp assemblies can be gently slid away from the vehicle.

After all applicable hold-down bolts and clips have been removed, it's time to slide your old headlamp assembly away from the vehicle - wiggling it gently as you go. Remember, unless you disconnected them earlier from behind, electrical wiring harnesses are still attached. Don't remove any bulbs from your factory housings just yet. Set your OEM headlamp assemblies aside, in the event that you wish to reinstall them one day, for example, if you decide to sell the vehicle.

Disconnecting And Reconnecting Electrical Wires

Tools Needed: Wire stripping tool, wire connectors, pliers (if applicable), electrical tape

Once you've pulled the old headlamp assembly away from the vehicle a short distance, it's time to get a full look at wiring harnesses that are attached. Even if you've removed one or more connectors from the rear of the assembly before unbolting it, there may be others (such as separate wires to side marker bulbs) still attached which were previously obscured. Once you can see everything, unhook any and all electrical connectors from the back of the headlight assembly. Usually, either a simple squeeze on the edges of the connector or pulling up on a tab is enough to cause the connector to release its grip, but if a thin wire bar is present, it usually needs to be slid into an unlocked position first. If you're not sure how a locking clip is designed to release, it's best to further research instructions for your make and model.

Headlamp Wiring Connector
This headlamp wiring connector from a 2001 Audi A4 is typical of most OEM equipment.
Metal Locking Clip
If you see a thin metal locking clip on your wiring connector such as this one, check with your vehicle manufacturer if you're not sure about getting it to release.

You are now ready to begin installation of the new lights. We will make all of the electrical connections first, while we have access to the backs of the assemblies. Then we will perform the mechanical install into the front of the car's body.

Custom Headlights
Custom headlight assemblies we sell are designed to fit into your specific vehicle as easily as original equipment, with mounting points that match your make and model's existing specifications.

Transferring Bulbs From Old To New Assembly

Depending on your year and model car, plus the design of the new custom lights, you may need to transfer some bulbs. In general, the new light will include low/high beam headlight bulbs. In many cases, the turn signal (incandescent) bulb is not included in the new assembly. This is very easy to rectify. You will need to remove the signal bulb from the old lamp (do NOT disconnect any wires) and install it, in its existing housing, into the new lamp. There may be a paper sticker which needs to be removed first.

The Plug'n'Play Portion Of The Installation

Both your old and new headlamps have low and high beam headlamps. When you removed the old units, you disconnected an electrical plug from the car or truck's wire harness. On the new assembly, you should find an electrical plug shaped exactly like the plug on the old assembly. This portion of the electrical install is called 'plug'n'play' because you literally only need to connect the new plug into the existing harness. If you have purchased lamps without any additional lighting elements like halos or LED lights, you are done with the electrical install.

Connecting The Extra Wires Found On Halo And LED Custom Headlamp Assemblies

When you install custom headlamp assemblies equipped with additional halo and/or LED lights ("bonus lights"), you're going to find extra sets of wires. In the typical installation, there will be one pair of wires for each additional light. Within each pair, one wire will be 'positive' (usually red or white) and one will be 'negative' (usually black). Assuming you want the LEDs and halos to switch on with the headlights, you'll be splicing both white wires together and both black wires together.

However, should you prefer these lights be triggered by your vehicle's daytime running lights (DRLs), parking lights, or even turn signals, the wires can be connected to separate power wires for those items instead. For example, if they're wired into the DRL harness, the world will see them anytime your DRLs are on during the day. Or, connect them to parking light wires to show them off when you're parked on the street at cruise night (they'll also flash every time you use keyless entry). Because wiring harnesses for different lighting functions vary from vehicle to vehicle, we recommend researching locations and wire colors for your specific make and model. Use a test light or multimeter (DMM, or digital multimeter) to probe the factory harness. Be sure to turn on the lights for the circuit you are pursuing so that it shows up as "live".

Once you've decided which wires you want connected, use a wire stripping tool (we offer a selection in our Wire & Cable Tools section) to remove an inch of the colored insulation at the end of each wire. The "power" wire needs to be connected to the light circuit. The "negative' or "ground" wire can be connected to any convenient vehicle ground point. However you choose to permanently splice the wires together, you'll find all the odds and ends you need (butt connectors, quick splice connectors, crimp caps, etc.) in the Connectors & Terminals section of our website.

Before bolting your new headlight assemblies back on the vehicle, check the back of them to see what type of knobs, screws, or fittings are there for the purpose of adjusting headlight aim. Look for applicable hand tools that provide grip, and put them to the side. Test all lights and turn signals to ensure they're functioning properly. Once that's been confirmed, tighten the new headlight assemblies firmly into place and reinstall all other components in the reverse order of removal.

Adjusting Aim Of Headlights Once Installed

Tools Needed: Tape measure, masking tape

Knobs, screws, and fittings on the back of headlamp assemblies that adjust headlight aim vertically and horizontally can vary greatly from design to design. Once you have the tools you need to rotate the specific adjustment knobs on your headlamp assembly in hand, grab a roll of masking tape and a 25-foot tape measure as well. We'll help you aim your new headlights without any complex or technical equipment.

1998 BMW 3-Series Headlights
This example of a 1992-98 BMW 3-series headlamp assembly shows round adjustment knobs for up-down and left-right positioning.
2006 Volkswagen Jetta Headlights
This VW headlamp assembly is an example of one that uses hexagonal rods for adjustment.

To do so, find a white wall and a level surface to park on - you can do this inside or outside, but the ground must be level and the wall flat and vertical. Measuring carefully, mark exactly 3.5 feet up from the bottom of the wall. Make two marks, and run a piece of masking tape horizontally across the two marks. The tape should be as wide as the vehicle plus an extra 2 feet per side.

Park the car so it's exactly 25 feet from the wall to the face of the headlamps—don't estimate. Begin to adjust the low beam using the adjusters on the back of the headlight assembly so the beam shines 3.5 feet high on the wall.

Headlight Aim Adjustment
Vertical Headlight Aim Adjustment
Low Beam Adjustment

We leave you with these words of wisdom: while we consider the installation of a set of custom headlamp assemblies a "DIY" affair, this kind of work is not for everyone. If you have had experience working on your own car, you will likely be comfortable performing this task on your own. If you are new to the hobby and want to give this a try, please use this article as a guide. You may also want to search out additional information on the Internet. If for any reason you are uncomfortable tackling this, please enlist the help of a professional. Whichever path you choose, have fun with the project, and enjoy the new custom lights on your ride!

Shop Now
Low Prices Price match guarantee
In-House Experts We know our products
Guaranteed Fitment Always the correct part
Easy Returns Quick & Hassle Free

All manufacturer names, symbols, and descriptions, used in our images and text are used solely for identification purposes only. It is neither inferred nor implied that any item sold by CARiD.com is a product authorized by or in any way connected with any vehicle manufacturers displayed on this page.

SECURE SHOPPING