H4 Headlight Relay Kits


Choose the HRK1 Kit if you own a vehicle with a dual filament HI/LOW beam mounted on each side. Choose the HRK2 Kit if you own a vehicle with a dual filament HI/LOW beam and a single filament HI beam bulb on each side.



Either kit includes the following:

  • (1) Pre-assembled Harness, loomed in Semi-Rigid Split Braid tubing, and terminated with OEM connectors
  • (2) 40 Amp Hella Waterproof Relays
  • (1) Waterproof ATC Style Fuse Holder & 30 Amp ATC fuse
  • All hardware required to install it

You absolutely, positively will not have to run to the hardware store to install this kit. How do we know? Simple. We’ve actually installed them ourselves.


Headlight Relay Kit Extensions

In some vehicles, the battery is in a location at which the harness will not reach both it and the headlights. In these cases, a Headlight Relay Kit Extension is required. These extensions are designed to plug directly into the harness of either the HRK1 or HRK2 to extend the main power lead. No special tools are required to install them.

Each kit includes a pre-assembled extension covered in split braided tubing as well as cable ties for an absolutely neat installation.

6 reviews for H4 Headlight Relay Kits

  1. 5 out of 5

    Gregory Park (verified owner)

    I installed the H4 wiring in my 1983 S10, which already had Italian Carello H4 headlights. Install was easy, time about an hour. No figuring out where to make the connections. The S10 is a project now, looking forward to seeing how the lighting is, especially the light effects that H4 lights make.

  2. 5 out of 5

    Connor (verified owner)

    Installed the headlight relay on my 72 El Camino. The high beams are much brighter than before and even the lows are noticeably brighter. Pleased with the kit and ease of install.

  3. 5 out of 5

    ron brandelli (verified owner)

    tonys the man! outstanding headlight relay kit! fit, finish and function is superb! 1964 el camino

  4. 5 out of 5

    M. Parrow (verified owner)

    I bought the HRK1 for my 1985 Ford F150, and it immediately, noticeably improved the brightness of my headlights. Furthermore, the kit is designed to remove the load from my stock headlight switch (which is prone to melting), allowing me to replace my sealed beam halogen headlights with brighter 65 watt modern replaceable-bulb headlamps (I chose Hellas). I could go up to 100 watt or maybe higher bulbs with this harness but don’t need to – the brightness is fantastic, but with a sharp cut-off (adjustable) so as not to blind oncoming traffic. I am so impressed with this HRK1 harness. It was easy to install, and when I had a question, Tony answered it by email immediately. This is a super-friendly and professional USA company. Are there cheaper (Chinese) headlight harness kits out there? Yes. But you get what you pay for. This harness is professional grade heavy duty and higher quality than my original Ford wiring.

  5. 5 out of 5

    Chris (verified owner)

    Impressed is a massive understatement. I just installed the HRK2 kit into my 1961 Buick, 4 headlights in literally just over an hour. Easy to follow instructions, everything is there, literally 2 screws to instal to hold down relays with everything else plug and play. I’m amazed at how simple and easy it was to install, especially for someone like me that truly sees electrics as some form of mystical black art. I would absolutely recommend this product. Thanks Tony

  6. 5 out of 5

    C. Gantt (verified owner)

    I bought the HRK1 kit for my 1968 Dodge D100 pickup. I called to ask for a better explanation of how the kit plugs into my stock wiring harness because I wasn’t keen to cut the original wires to splice in the new relay kit. Right away it was explained to me that one of the original female plugs which plugs into a headlight bulb, plugs into a male plug which is part of the kit. A novel approach if you ask me. I was impressed with the quality of the workmanship, the materials used, and the speed with which it was shipped. There are cheaper relay kits out there but I’m glad I purchased this one. From the professional wrapping, quality braided loom, and extra lengths supplied, I couldn’t be happier.

  7. 5 out of 5

    Rick Allen

    I installed the H4 headlight relay kit in my daughters’ 1977 VW bus. Fantastic, the headlights are much brighter making the bus much safer to drive at night. The kit worked perfectly without a hitch. Terrific product.

  8. 5 out of 5

    Scot Allyn

    Tony’s HRK2 relay kit really woke up my headlights! I installed the kit on my 1984 Dodge about two months ago, and am still pleasantly surprised when I drive at night. The high beams, especially, are hugely brighter on the dark back roads of Ohio. The instructions were easy to follow and I didn’t need to add anything, not even a washer. Thank you, Tony, for helping me keep my 32-year-old daily driver on the road!

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