Headlight relay harness questions

Good morning, I have been fighting my headlights. I was given a st if New in the good hella from the diesel mechanic at with. I through them in the burban. however am for as three prong. So from my research in here, I need to replace two bulbs with high beam only. Also I should get a relay it. The question is do I need the lmc relay kit die each side? Or does one kit do the whole truck? I am not handy with wiring or I would make my own. Hell I probably have all the parts. However it is not worth my frustration lol

Do your Hella's have an H4 bulbs? I'm assuming all 4 lights have high are H4's based on the end of your comment.

The H4 pin location is different than what your truck came with. I had ordered a kit from Amazon for my truck, but by the time I installed it, I couldn't remember if I bought it for a stock set up or for an H4 bulb. The Hella Lo/Hi beam bulb originally came with a short pigtail to convert the H4 bulbs to the stock wiring. The kit I purchased had the ability to move the pins in the connector at the bulb. Once I did this everything worked fine. My kit came with two relays. They are connected, but each powers just the high or low bean circuit. Only one relay is on at a time.

Here's a copy of the factory wiring for my '85. Your headlights should be wired the same. Sorry I don't have a diagram for the changes I made.

I'm not sure the two-prong H1 high beam bulb installs the same as the 3 prong low beam in their respective housings. The H4 openings are bigger.

My wiring kit is similar to the one pictured below. If you notice the connector on the lower right, it is for a high beam (there is one connector missing in the plug). This will work if you have four H4 bulbs as it will slide right over the prongs. If you get ambitious, that second low beam could be made to work with some extra wiring. Hope this helps.

Using the harness will make a world of difference. I have a video here with just 2 headlights on my 71. Here is the vid if you would like to see the difference. Start with the relay. You
dont really need to upgrade the headlights to H-4, but it makes a HELLA difference.

I do have four bells h4 bulbs. Thanks in going to research some harness.


Update I have found some on Amazon that have one h1 connection to two h4. I understand that this would allow the relay setup to control hi or low beam. Is this how it is supposed to work???

Hi and Lo are two separate circuits. Typically you’d need a separate relay for each circuit.

When you switch from low to hi, it turns one relay off and the other on. The relays are linked. I had to draw out the circuits on paper to understand their paths.

If running one of the premade(h1 to two h4 ) relay kits. Will all four be o. When brights are on? Does the bright light indicator light up on the dash?

If I wire my own relays to each of the four headlights would solve of that correct?

Kevro_N_Chevro said:

If running one of the premade(h1 to two h4 ) relay kits. Will all four be o. When brights are on? Does the bright light indicator light up on the dash?

If I wire my own relays to each of the four headlights would solve of that correct?

Click to expand...

If you by one of the kits, all 4 high beams come one at once. Yes the Hi-bean indicator works. You only need 2 relays. Basically you are only using the OEM wiring to turn the relays on/off. The power to feed the new lights comes directly from the battery. Each headlight socket on the harness has a separate ground.

Looking at this kit. Thanks guys

https://www.amazon.com/Headlight-Ha...uPWNsaWNrUmVkaXJlY3QmZG9Ob3RMb2dDbGljaz10cnVl

Kevro_N_Chevro said:

Looking at this kit. Thanks guys

Click to expand...

That harness is only for 2 head lights based on the pictures. You need one with 4 headlight plugs.

The plug in the photo may have to be re-pinned to match your OEM harness. This plugs into the Lo-Hi beam light socket. H4 bulbs have different prong locations. It only takes a small screw driver to depress the lock holding the metal pin.

https://www.amazon.com/4-Headlight-...Headlight+Harness+H4+Headlight,aps,236&sr=8-7

Good catch! I ordered get one. Thanks