Headlight Wiring Harness

In this article, we’ll review the headlight wiring harness.

Don’t be surprised if your car’s upgraded HID lights start flickering one day. Only to find out that your headlight wiring harness has melted and needs replacement!

That’s why we made this quick guide about headlight wiring harnesses and how to choose the correct replacement for your car.

By the end of this article, you’ll understand the use and differences of various headlight wiring harnesses.

Continue reading to start learning about the headlight wiring harness.

What Is A Headlight Wiring Harness?

We all know stock halogen bulbs aren’t bright enough to be reliable for everyday trips. That’s why many drivers are switching to HID headlights. And you’ll need a wiring harness to attach this new system to your car’s sockets.

Since HID systems utilize unique technology to power their bulbs, you can’t just insert them into your car’s original sockets. That’s why wiring harnesses are essential in energizing these headlights properly.

Each harness contains terminals and circuitry that communicate with your car’s system to power your brand-new HID bulbs correctly. They act as a converter to connect the ballasts to your vehicle’s assembly sockets.

The wiring harness also ensures that your headlights are receiving enough electricity to function. Making them critical in securing the functionality of your vehicle’s brand-new HID headlight assembly.

Here’s what a headlight wiring harness looks like:


The wiring harness in the image is an upgrade for the 2008 to 2012 Chevrolet Malibu. You will also find other harnesses in different socket sizes specific to your vehicle model.

There are a ton of different first-party and aftermarket manufacturers that sell headlight wiring harness replacements. They offer various harness models to accommodate other socket and headlight assembly sizes of vehicles. Letting you choose the appropriate upgrade for your car.

Where You Can Find The Correct Headlight Wiring Harness For Your Vehicle

Although most wiring harnesses have the same function, it’s still crucial to use the model that’s compatible with your vehicle. Using an incompatible harness may render your upgrade useless. You should first obtain a copy of your car’s headlight wiring diagram.

You can quickly grab a copy of your vehicle’s headlight wiring diagram from the manufacturer’s official website. Always indicate your car’s make and model to get the precise schematics you need.

You’ll find your car’s headlight socket size with the help of the wiring diagram. This informs you of the appropriate wiring harness size that will perfectly fit your vehicle’s assembly.

Once you’ve identified your car’s headlight socket size, you can search for compatible aftermarket or first-party headlight wiring harnesses. These replacements also have their schematics on their official websites.

This lets you compare the harness upgrades’ diagrams to your car’s requirements. Precise compatibility ensures that the replacement you’re purchasing works flawlessly with your vehicle.

Why You Should Use The Correct Headlight Wiring Harness For Your Vehicle

There are a ton of headlight wiring harness upgrades available on the market. Making it confusing as to which replacement you should purchase. And using an incompatible wiring harness with your vehicle can cause many problems.

You may experience dimming or flickering lights. It’s even possible that your HID bulbs won’t power on because of the lack of electricity that the incompatible harness provides. Or worse, it may ruin and short-circuit your vehicle’s system.

That’s why it’s crucial to compare your wiring harness upgrade to your vehicle’s headlight requirements before installation. Ensuring that you won’t run into any complications while on the road.

We highly recommend obtaining a copy of your car’s headlight wiring diagram to identify your assembly’s socket specifications better. It’s also best to review the performance of various wiring harness upgrades to determine which one is worth purchasing to avoid functionality issues.

Now that you’ve learned more about headlight wiring harnesses, upgrade your vehicle! Remember to choose the appropriate replacement for your car’s make and model to avoid compatibility issues.

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Richard Nickleson is the author and owner behind Headlight Reviews. He first started the site as a hobby to share his insights on car parts and specifically headlight bulbs, but it soon ballooned and now he writes on all topics surrounding headlights bulbs. If you've got a bulb question, contact Richard here.