LMC Heavy Duty headlight harness

[Bitch'nBronco]

Does anyone have the color chart for an LMC Heavy Duty wiring harness? I've searched for a while and can't find it. I can't get my low beams to come on, but the high beams work. Grounds are good, I just want to figure out which wires are associated with the low beams. Thanks

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[RonJones]

I don’t have that vendor’s unit (I have a JBG and a TBP), but I think one relay is used for high and the other for low beams. I’d suggest remove one relay, and if that kills the working beam, then the other circuit is the problem child. You might
also try swapping relays, as those are the only “moving parts” in the harness, and one of those is likely the issue.

 

[Bitch'nBronco]

Thats a good idea, thanks!

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[75MIKE]

Make sure your dimmer switch is switching over for low to highs. They can get tired after a while.

 

[Bitch'nBronco]

The switch is good, I was hoping it was that easy lol. I get low beam power all the way to the HD harness, both relays click anddd... no low beams lol

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[75MIKE]

If you have power to the low beam at the socket it's got to be the headlights themselves I would think.

 

[RonJones]

Clicking might not be the best measure of relay function. Typically pin 30 carries the power to be switched to the relay, and pin 87 carries the current from the relay to the accessory, in a normally open circuit, once the relay coil is energized. If you don’t want to try switching the relays, you might consider checking the voltage at those positions to see if power is going from pin 30 to 87.

 

[Bitch'nBronco]

I swapped relays and didn't get a change. I'll test the pins, thanks for sharing that!

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[B RON CO]

Hi, or just remove the relay and jump the hot feed to the low beam feeder.wire. Good luck

 

[Bitch'nBronco]

I know thats an option and I guess that'd tell me if it was maybe a ground issue. My dad installed the harness, cut the plug off that was supposed to plug into the existing harness and I want to make sure it got soldered to the correct wires. I'll still give that a shot though. I just installed these lights and want to get the low beams working (low beams haven't ever worked lol)

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[B RON CO]

Hi sorry I didn't say jump it just to test it out. Not permanent. The headlight relay system it great. It takes the high amp load off the headlight switch. Good luck

 

[RonJones]

Given the relay switching didn’t change anything, I think I’d switch the lights and see what that does.

 

[DirtDonk]

That's a lot of light! Did you get them working, or was that just the jumper test?

If you still need to know which wire is which on the new harness, I don't know about the new, but whichever circuit the Red w/black wire is connected to is the low-beam circuit.
Green w/black should be high-beam if I'm remembering my colors correctly an don't have them reversed again!
Since you've had it apart and been testing, you probably already know which is which now. But if not you should be able to trace which relay is fed by each of those wires.

Paul

 

[Bitch'nBronco]

Thanks! And the high beams work perfectly, I'm going to keep testing this afternoon. I appreciate the input. These are the lights

https://www.ebay.com/itm/Dot-Approv...-f4df-4b63-9ddc-d2ea8c7b2e7e&epid=12018283437

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[Bitch'nBronco]

Well, narrowed it down to a relay. Unfortunately nobody carries that version of the relay so I've decided to change them out to a pair of RL44s. I want to verify I've got the pins correct.

87 hi/lo out (to lights)
85 hi/lo in (from switch)
30 batt pwr
86 GND

I'd appreciate the help. Thanks

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[Bitch'nBronco]

Here is a generic diagram for the RL44

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[79INA69]

Are your high and low beams coming on at the same time? If the back of your headlamp has a 3 wire set, you should only have power at the leg it is switched to. Originally green is High and red is Low, black is ground. If you put your meter or test light on the ground wire for the harness and probe the other 2 legs, you should only have power at one leg. If you have power on both, then one of your wires at the harness or bulb side has been crossed. You can simply jump the foot switch harness to ensure power is only going through one leg there too.

 

[Bitch'nBronco]

Its only going thru one leg at the switch, I'll check at the pigtail for the bulb. If its helpful at all I get a loud click for the high beam and a quiet click for low

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[gr8scott]

Are your high and low beams coming on at the same time?

A lot of LED headlights, including his, do this be default, but only when high beam is activated. They should not be both on in low beam mode.

 

[Bitch'nBronco]

They are not both coming on at the same time. Going to work on it some more this afternoon

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