LMC Heavy Duty Headlight Harness Problems

[SulphurDave]

I tried and tried to figure this problem out on my own going on 2 weeks now. I've done some researching online and on this site and have finally windled down to nothing... as in, I'm out of ideas of what's causing my problem.

Short story long, I purchased the 4 square type euro lights with push-in style bulbs and the recommended harness to go with it. Needless to say the instructions might as well not even be printed on the back because it was lacking lots of instructions and whoever wrote the English must have flunked English Grammar 101 over there in Taiwan. Anyway... I wired everything up the only way that made sense to me and the only real questionable thing is where I plugged the harness into the existing low beam headlight harness on the passenger side. The other is where each harness was plugged into the headlights.

OK here's the problem. The first time I turned the headlights on the bottom lights (high beams) turned on and then when I clicked the high beams on the top lights came on leaving all 4 lights on. I figured this was wrong being that the top lights are the low beams. So I switch the plugs around on the headlights. That corrected it but for a while there sometimes it would work and sometimes the low beams wouldn't come on at all just the high beams. I end up running out of patience.

The next day after being fed up with it the day before, I tried it again and now the low beams were not coming on plus the parking lights were flickering and I traced the clicking noise (flickering) all the way to the headlight switch. So I bought a new headlight switch. Tried it, no low beams, still flickering, turn high beams on, they come on & flickering stops. Got fed up again.

Next day I open the door, turn the headlights on (low beams) to check and to my surprise they come on after doing nothing. I stand back puzzeled. Low beams work, high beams work & no flickering. Yay! But that was short lived. I go to crank the motor and everything trips (I have a circuit breaker for my main power). Now I'm really puzzeled. I reset the breaker, try to start the motor and it trips again. I reset it once again but this time unplugged the power to the headlight harness. Motor cranks right up. So... looks like I have multi-problems. And I'm out of ideas. Anyone?

[pcmcobra]

you got any pics of the wiring, did you cut any wires? Maybe you need relays, if you don't already have them.
I just put headlight relays on my truck, no problems yet.

[SulphurDave]

Originally Posted by pcmcobra

you got any pics of the wiring, did you cut any wires? Maybe you need relays, if you don't already have them.
I just put headlight relays on my truck, no problems yet.

It came with relays. No I didn't cut any wires it's all plug and play. I went to RadioShack to look for some to replace them in case they were faulty but no one carries the exact ones I need. That I know of anyway. Here's a pic off of LMC's site

[piecesparts]

I have that very same setup sitting in my garage. I purchased it and then decided that I would not install it at this time. I have put in several wiring harnesses for the headlight upgrades in later model trucks and have had no problems with them. However if the LMC wiring setup is the same as the one that I have, the package was mostly in Oriental languages.
It sounds to me that you are not getting a good electrical signal to your relays for your headllights. I would look at the area first. Ensure that you are connecting the power source for the headlight to a good 12 volt battery source. Second look at the relay and note that it needs a good ground for the relay control circuit to work right. That means possibly putting a ground wire to the body and the power will come from the headlight switch (however the healight circuit should cover that).

What I would do is put the harness in and then connect each control relay circuit (low beam and high beam) to a good 12volt source, with jumper wires, and see if the lights work right and stay on. Once you are sure that is right, then connect it to the headlight circuit and work your way bck to the switch.

[SulphurDave]

Originally Posted by piecesparts

if the LMC wiring setup is the same as the one that I have, the package was mostly in Oriental languages.

You are correct

Originally Posted by piecesparts

Ensure that you are connecting the power source for the headlight to a good 12 volt battery source.

The main power from the harness is bolted directly to the positive battery terminal

Originally Posted by piecesparts

Second look at the relay and note that it needs a good ground for the relay control circuit to work right.

The ground wires from the kit are bolted onto the same factory grounding wires from the original harness on the core support.

Originally Posted by piecesparts

What I would do is put the harness in and then connect each control relay circuit (low beam and high beam) to a good 12volt source, with jumper wires, and see if the lights work right and stay on.

I did this prior to installation. Before permanently installing the harness I hooked up the lights directly to the battery to see if they worked and stayed on and they did.

Like I said, after installing the harness in the truck, I tried the lights and they all worked but it was backwards. (low beams were the bottom lights and high beams was the top lights) I then reversed the plugs on the lights themselves (made sense to me) and then they worked right but not for long. Sometimes they would come on and somemtimes they wouldn't. Clicking back and forth from low beam to high beam you can hear one relay clicking but when going to low beam I don't hear the click nor do the lights come on. Sometimes the lights will even flicker and the flicker sound comes from the headlight switch. I put a new headlight switch in and that didn't help. Meanwhile if the power source from the harness is connected to the battery the truck will not start and trips my circuit breaker. Unhook the harness from the battery, truck starts.

[knightlife]

honestly...its easier to just run without it...hell the instructions are in japa-friggin-ese! hell...the lights hook right up without the harness breh...if nothing else, just put the old connectors on and run with your new lights...

[SulphurDave]

Originally Posted by knightlife

honestly...its easier to just run without it...hell the instructions are in japa-friggin-ese! hell...the lights hook right up without the harness breh...if nothing else, just put the old connectors on and run with your new lights...

1... the old connectors were dry rotted and most of them fell to peices as I pulled them off the old lights. 2... the main reason for doing this is because I wanted the lights to be much brighter which they are when they're working. 3... I'd rather do it the right way than settling for something else.

[jb4short]

the fact that the symptoms seem to change makes me believe it's a ground issue.

[Restrorob]

How many relays are you running in this system ?

[SulphurDave]

Originally Posted by Tri-ProAutomotive

the fact that the symptoms seem to change makes me believe it's a ground issue.

I tend to make myself believe that as well but being that they are grounded on the factory bolt on the core support make me wonder. Is it possibly because both the factory harness ground wires and the heavy duty ground wires are grounded together on each side? (2 on each side)

Originally Posted by Restrorob

How many relays are you running in this system ?

Originally none unless there's one under the dash somewhere that I don't know about. But the kit comes with 2 of them as seen in the above pic.

[jb4short]

Originally Posted by SulphurDave

I tend to make myself believe that as well but being that they are grounded on the factory bolt on the core support make me wonder. Is it possibly because both the factory harness ground wires and the heavy duty ground wires are grounded together on each side? (2 on each side)



Originally none unless there's one under the dash somewhere that I don't know about. But the kit comes with 2 of them as seen in the above pic.

anything is possible over time on a vehicle....even mild corrosion can eventually wind up isolating a bolted in component. Alligator clips from the neg lead on the harness to the neg battery post would be the most definitive test (and an inexpensive tool to keep around). If you can't recreate the issue while jumpered that way than you know that's your issue.

[SulphurDave]

Here some pics I just took of my truck that I labeled.





Here's the wiring diagram for the harness.

[Roper]

I was planning on buying one of those LMC EUROstyle headlight kits for my truck. No way im doing it now!

[SulphurDave]

Originally Posted by Tri-ProAutomotive

the fact that the symptoms seem to change makes me believe it's a ground issue.

I made 2 new grounds for the h/d harness wires and left the ground wires from the original harness bolted in the factory spot. Same thing. Low beams come on and when I flick the high beams, those lights go off and high beams do not come on and the parking light bulbs flicker.

*5:36 PM Edit* Yesterday to get the truck to start I had to unplug the h/d main power harness going to the battery. If it was plugged in and I tried to start it, it tripped my circuit breaker everytime. After relocating the ground wires like I just mentioned above, I unplugged the harness to see if the truck would start like yesterday. It tripped. I did this over and over a few times having to keep resetting the breaker. Then I plugged the h/d main power harness back in just to see how my luck was and it cranks up which is totally opposite of what was happening yesterday. Oh yea.. and the high beams still don't come on. I'm drenched with sweat, tense from wanting to throw my tools across the yard and my patience has run out on this little headlight project.

[Roper]

Did your old lights work good before you put on the LMC stuff?
Man I wish I could help you.
Okay this is probable super dumb but is it possible your high/low beam selecter thats on the floor? Sometimes when they get bad they can make your lights do wierd things although I never heard tell of one doing what your lights are doing.

[SulphurDave]

Originally Posted by Roper

Did your old lights work good before you put on the LMC stuff?
Man I wish I could help you.
Okay this is probable super dumb but is it possible your high/low beam selecter thats on the floor? Sometimes when they get bad they can make your lights do wierd things although I never heard tell of one doing what your lights are doing.

The lights worked prior but one of them was burned out that's all. The high beam selector is not on the floor it's on the column.

[jb4short]

sounds like a short in your HD harness....let me try to think this through

[SulphurDave]

Originally Posted by Tri-ProAutomotive

sounds like a short in your HD harness....let me try to think this through

Could it be simply the relays? When I click back and forth from low to high beams I can hear at least 1 of them click the lights on. Not sure which one since they're so close together but it seems like I'd hear another click for the high beams coming on and I don't. At least I don't think.

[jb4short]

you can test that by swapping the relays to see if the condition moves from the high beams to the low beams

[SulphurDave]

Originally Posted by Tri-ProAutomotive

you can test that by swapping the relays to see if the condition moves from the high beams to the low beams

I've done that before and nothing changes. Low beams come on and high beams don't.

[SulphurDave]

Can anyone else shed some light on the subject?

[Thealien]

I would check for voltage with a meter at each relay. is the power going to the relay? When the relay is powered does the relay coill actually get voltage? If so is voltage leaving the relay?

IMHO with what you describe there is no power (for the lights) going to the second relay.

It does look difficult to test those relays but you could unplug the relay and check at the plug.

Good luck.

Since one relay seems to be working I would check for power on that plug with the lights off and on, on high beam the other relay should have power in all the same places.

[SulphurDave]

Originally Posted by Thealien

I would check for voltage with a meter at each relay. is the power going to the relay? When the relay is powered does the relay coill actually get voltage? If so is voltage leaving the relay?

IMHO with what you describe there is no power (for the lights) going to the second relay.

It does look difficult to test those relays but you could unplug the relay and check at the plug.

Good luck.

Since one relay seems to be working I would check for power on that plug with the lights off and on, on high beam the other relay should have power in all the same places.

Yea I'm waiting on one of my buddies to come over with his tester. We're gonna check all that out and see what's happening.

[84_chevrolet]

Hey man did u ever get everything to work right? i installed one of lmc harnesses last night and it worked great for me. How do u like the euro headlights are they worth the money?

[SulphurDave]

Originally Posted by 84_chevrolet

Hey man did u ever get everything to work right? i installed one of lmc harnesses last night and it worked great for me. How do u like the euro headlights are they worth the money?

Honestly I have no idea what fixed it because I've messed with so much in between and other things not really related to this problem that one day they miraculously started working. Can't explain it though. That's not to say they will work next week though. I think that if you maintained the sealed beams but juiced them up with the extra voltage from the harness the light output would be comparable to the "bulbs" that came with the euro lights from LMC. You can always upgrade the bulbs to a brighter blue'er hue like the h.i.d. look-a-like bulbs the imports use if you wanted that.