LMC Heavy Duty Headlight Wiring Harness
 

Just installed LMC’s Heavy Duty Headlight Wiring Harness. The install went well except for one of the ground wires was too short - easy fix. When I turned on the headlights I found that the high beams worked fine, but I have no low beams. Anyone familiar with this setup? Advice to solve the problem?

Re: LMC Heavy Duty Headlight Wiring Harness
 

try switching the relays to see if you got lows and no high if so its a bad relay if not going to have to check wire harness

Re: LMC Heavy Duty Headlight Wiring Harness
 

I bought on on ebay for $20 for my gmc had no problems.

Re: LMC Heavy Duty Headlight Wiring Harness
 

Make sure the relays are not swapped one should be a 4 prong other should be 5 prong relay. I had the same problem .

Re: LMC Heavy Duty Headlight Wiring Harness
 

And don't forget a fuse for them, if you haven't put one in already.

Re: LMC Heavy Duty Headlight Wiring Harness
 

Thanks for the advice. I hadn’t thought of the relays.

Re: LMC Heavy Duty Headlight Wiring Harness
 

The relays are identical. Both of the plugs that go into the relays have 4 plugs.

Re: LMC Heavy Duty Headlight Wiring Harness
 

mine is from lmc also it has only 4 on both . the extra pin is for a normally closed circuit . you shouldn't need the extra pin because you have a dimmer switch that feeds power to one relay or the other . if it is wired correctly it wouldn't matter if you used a 4 pin or 5 pin relay the connector wouldn't have a wire for the pin so either would work as long as it was rated for the same amperage

Re: LMC Heavy Duty Headlight Wiring Harness
 

I installed this kit recently. I went and looked, and discovered it does not have fuses. I'll be adding fuses into the circuits. Good info!

Re: LMC Heavy Duty Headlight Wiring Harness
 

I installed this kit into my GMC this weekend. I’m curious as to
where in the circuit I should install the fuses and what rating fuses would be appropriate. Thanks!

:gmc2:

Re: LMC Heavy Duty Headlight Wiring Harness
 

Wrote out a long post that didn't post. shorter version...

Test the power coming out of the head light switch. Test each of the inputs to the relays. Swap relays to see if the problem follows the relay. If you remove and reinstall the relays while the headlights are on, you should hear the relay click as power is applied.

Fuses, I like to install as close to the battery or junction as possible. Headlights should draw around 10A. 15-20A should be good.

Re: LMC Heavy Duty Headlight Wiring Harness
 

Thank you rpmerf! That is what I was thinking, but it never hurts to get an expert opinion.

Re: LMC Heavy Duty Headlight Wiring Harness
 

Just got back to this thread. I haven't put any fuses in yet, since I have been doing other things. Thanks rpmerf for the information!