Skip to main content

Free Shipping on every order over $50 in the Lower 48

and pay NO Sales Tax!


Josh's Relay Kits Headlight Relay Harness

Part Number:
Calculated at Checkout

Have a Question? Ask a product expert! Call or Text 253-320-7604

Product Details

Restore your headlight brightness with our Headlight Relay Harness built by Josh's Relay Kits & Automotive Electronic Services.  These are the best relay kit on the market and are easily adaptable for most lighting upgrades / bulb styles! 

Set up for the standard H4 / H6054 type bulb, they also feature an interchangeable headlight socket design.  By disconnecting the 3-pin Weather-Pack connector, you can change to a different style connector allowing you to run most any style of headlamp you want. 

The connectors are high quality, high temp units. 

These fit the factory sealed beam headlamps as well as aftermarket (Hella, Cibie, Koito, etc) headlamps.

The biggest improvements these relay kits have over others on the market are:

  • Size and Type of Wire
  • Type of Heat Shrink Tubing
  • Use of Heat Shrink Fabric for Added Protection
  • Waterproof Housing for Fuses and Relays
  • USA Made (Other Than Relays Themselves) 

All of the materials and supplies are of the highest quality available for non-race car applications.  Each kit is built with 12 AWG GXL cross link type wire, except the main power and ground, which are larger 10 AWG.  GXL wire features a medium thickness chemically cross-link polyethylene insulation, which provides additional protection and resistance against moisture, solvents, and high temperatures.  It is built to withstand prolonged temperatures up to 125°C (257°F) without melting or fusing. 

GXL Wire Features:

  • Temperature Rating: -40°C to 125°C (-40°F to 257°F).
  • Voltage Rating: 60V DC.
  • Meets or Exceeds SAE Specification J1128, Ford ESB-M1L85-B, & Chrysler MS-8900.
  • RoHS Compliant.

Heat Shrink Tubing Features:

  • Flame Retardant
  • Superior Sealing Against Water, Moisture, or Other Contaminants
  • A High Shrink Ratio Allows for Coverage of Irregularly Shaped Connectors and Components
  • Inner Adhesive Bonds to Plastics, Rubber, Neoprene, Steel, and Polyethylene
  • Continuous Operating Temperature: -55°C to 110°C

Heat Shrink Fabric Features:

  • Highly Flexible Woven Fabric
  • Polyethylene / Polyester Construction for Excellent Abrasion Resistance
  • Resistant to Harsh Environments
  • Resistant to Trapping Water, Heat or Humidity
  • UL (E199379) Rated at 135°C

Installation Video Below (Note harness shown is an older design, but installation process is the same).


  • Fits All Full Size Jeeps

Reviews (6)

  • Best Upgrade to an FSJ

    Posted by Cesar on Jan 18th 2024

    If you driven an FSJ with original headlights at night you know how difficult it is to see. I was not sure how much the relays would improve the lights, but installation was simple and the original headlights got brighter for sure. I'm very happy and I would recommend this upgrade to everyone with and FSJ. It's night and day difference.

  • Excellent Harness

    Posted by Unknown on Mar 7th 2023

    This is a very well constructed and high quality harness. The one I received was 100% plug in as opposed to the illustration here where the relay signal inputs need to be spliced. That's an improvement. The power connections to the battery are too small a diameter for standard battery post bolts but are easily reamed out to fit. I would strongly recommend this piece of equipment even though its a little pricey compared to other products. Installation was pretty easy but removing the headlight bathtub fittings will simplify the job.

  • Crawdad

    Posted by Unknown on Sep 25th 2022

    installation is plug and video

  • Jeep Guy

    Posted by RL Howard on Jan 26th 2022

    I was having issues with my headlights turning off/on while driving after I upgraded my headlights. These relays solved the problem and were very easy to install. Now my new lights work great and are bright as a new truck. Not cheap, but these are very high quality.