Heavy Duty Headlight wiring harness

[forest522]

For once this is not yet a problem but just a question to avoid a possible problem. I searched the CUCV forums for "heavy duty headlight wiring" in a variety of combinations and didn't see anything that addresses this.

I have upgraded my headlights to the fancy ones in the LMC catalog. They work, but I wonder if there is a need for the heavy duty wiring harness on our CUCVs. Of course in the catalog they recommend Blazer owners upgrade to their heavy duty kit that draws power directly from the battery instead of the headlight switch.

I know our CUCVs have standard headlight switches like all the other K5s out there, so the question is, is the CUCV wiring more stout that the civi wiring, and secondly, is it better to go with this upgraded, heavy duty harness to properly feed the new headlights? Has anyone upgraded?


New headlights are those in my avatar and this is the wiring harness and the page from LMC catalog...

 

[cpf240]

The factory must think that the stock wiring is, or was at time of manufacture, up to the task of handling the draw from the headlights. Once age, corrosion, etc comes into play in vehicles this old, I don't think they are up to it.

I have a '72 240Z, and they are known for melting the fuse box due to the high draw of even the stock headlights.

A few months ago I installed the wiring kit from LMC. It works, but you get what you pay for. I looked at some of the stuff sites like Summit sell, and they are two or three times the cost of the LMC kit. Are they worth it? Maybe.

I feel that the LMC kit is made to fit its bargain price. I would not buy it again. Nor would I buy the more expensive ones out there. After looking at it, I think I could easily build my own, using heavier gauge wires, Bosch relays, and headlight terminals that are not open on the back exposing the terminals to the elements.

Just my

 

[doghead]

I think those relay kits were introduced shortly after their Chinese(inferior) headlight switches hit the market.

No, you don't need it.

Today's replacement headlight switches are mostly made in Mexico(where standards are....

 

[forest522]

Thanks for the replies! Seems like good insurance policy would be to have a spare headlight switch in the toolbox!

Shame that these parts are made elsewhere...ugh

I have been thinking the same thing...making one myself! So, a quick google search and this is what turned up:

Headlight Loom upgrade

Not sure, but seems like the concept is right.

 

[K9Vic]

Well..... let me say this.

I installed the glass H4 headlights on my M1009 and the fuse got real hot and I had to make a relay harness to take the load off the fuse panel. So as I have said before in other posts, yes IMHO you need one. Since that time I have installed a the relay harness in my other trucks when I upgrade to the H4 headlights.

The one from LMC is a cheap Chinese harness, but I have one in one of my trucks and no problems with it. My other two trucks I made the harness as I had the parts.

 

[cpf240]

I have been thinking the same thing...making one myself! So, a quick google search and this is what turned up:

Headlight Loom upgrade

Not sure, but seems like the concept is right.

That looks about right! I'd prefer to find a better way to connect to the existing headlight wiring than just using spade terminals like that site shows. The LMC, and others, come with a connector that mimics the back of the standard headlight bulb. I'm sure they are available with a bit of searching.

Oh, and I should add that while it may be subjective, or hoping that my money was not wasted, but my lights seem brighter with the use of the LMC harness over the stock wiring.

 

[xenocath]

i bought the lights from lmc for my 81 chevy 2wd truck about 10 years ago since then these have moved from truck to truck untill they landed in the m1008 have had no issues with either the lights bulbs or harness that i bought from lmc and am extremely happy with the quality of light they give over stock i tried without the harness at first wires got hot so i retrofitted the correct harness from lmc in and no issue with that since.

 

[MarcusOReallyus]

Headlight Loom upgrade

Not sure, but seems like the concept is right.

Yep, that's the idea. I didn't look at that page in detail, but that's the right idea. It's not complicated, really.

I think it's a good idea with stock headlights. If you are upgrading, I consider it mandatory.

Remember the dielectric grease on the connections! All the connections.

 

[MarcusOReallyus]

Oh, and I should add that while it may be subjective, or hoping that my money was not wasted, but my lights seem brighter with the use of the LMC harness over the stock wiring.

I suspect that's real, not just wishful thinking. Measure the voltage of a stock system right at the headlight, and then measure it with the upgrade in place, and you'll probably see something like a two volt difference. That translates directly to more current through the headlight, which means a brighter headlight.

 

[biggestc69]

I upgraded my headlights to the ones that Napa claims are brighter and I could tell a little difference. That was about 4 months ago. By the grace of God I stubmled upon the weak headlight wiring circut thread and purchased a LMC upgrade as per its instructions. You guys have never steered me wrong yet. This weekend I was going through the fuse panel and cleaning up some wires under the dash and when I got to the 30 amp headlight fuse it wasnt blown but the plastic had gotten hot enough to warp it. YIKES! I've had the LMC upgrade kit sitting on the bench for 2 months now, tonight, its going in! I've lucked out so far I guess. And those Napa lights aren't that much brighter than the stock ones. So I'd say if you do ANY kind of headlamp upgrade use some kind aftermarket kit or figure one out on your own, shouldnt be too hard with some relays and bigger gauge wire. I'm not an electrical genius by any means so catching this here on the forum and getting the upgrade prolly saved my harness or at least didnt leave me driving home with my head hanging out the window using my spotlight to limp home. Thanks again Steel Soldiers for saving me and my trucks 6 once again!

 

[twomorestrokes]

These trucks are wired differently than the civi cousins.The upgrade is a great idea on these trucks due to all of the different circuits that normally run through the single 30a fuse. (headlamps, turn signals, horn, etc etc) It all stays under 30a so the fuse does not blow, but due to the high load on this single circuit, once the connections start to deteriorate the fuse gets hot enough to melt the fuse and fuse box. This upgrade takes most of the load out of that single circuit.

My truck had a heat damaged circuit when I bought it. The headlamps would go out at the most inopportune times! (usually at night.)

 

[1StumpJumper]

I recently did the LMC relay kit. The package said to plug into the drivers side headlight plug. I instead plugged it in to the passenger side then routed the wires under the Battery 1 tray and connected the power feeds to the battery instead of the 12v power tap on the firewall.

The headlights are definately brighter, I would say 15-20%. The new fuse shows no signs of melting like the old one did. I will perform this modification on all of my older vehicles from now on.

 

[richingalveston]

I did the same with mine, pluging into the battery using one of the side post. I also used the ground screw in front of the front batery and had no issues with the lengths of the wire. I do see the need to add a fuse. Doing this bypasses the fusable link that is between the batteries and the 12volt terminal block. I have not added the fuse, Will probably just use some of the fusable link material that I have instead of a plug in fuse.

 

[1StumpJumper]

Good point on the fuse Rich, I had thought about that then forgot during the install.

 

[cpf240]

Mine came with two short in-line blade fuse segments, that connect to the battery positive, and plug into the rest of the new headlight harness. Are there different versions of these kits?

Update - never mind, I was mistaken! No fuses came with the kit. I'll have to add them!

 

[natemccabe]

How is the headlight logevity with the upgraded harness? I had the sylvania silver stars in the 1009. They were definatley brighter but only lasted a little over a year. Same thing in in my wifes car I put the brighter bulbs in, h4's, and they only lasted a year. Brighter yes, having to replace after 12 months, not sure if it was worth the extra money. How does the extra current effect the longevity of the lamps.

 

[MarcusOReallyus]

Extra current is going to shorten the life of the headlights. No question.

How much? Dunno.

But it's still a lot cheaper than burning up a wiring harness or headlight switch.

 

[scottladdy]

Mine came with two short in-line blade fuse segments, that connect to the battery positive, and plug into the rest of the new headlight harness. Are there different versions of these kits?

Would you be able to share pictures of these fuses? Thank you ...

 

[cpf240]

Would you be able to share pictures of these fuses? Thank you ...

Ok... color me embarrassed...

I just went out to take a picture, and guess what? I was mistaken... no in-line fuses. I was so *sure* that they were there, in that short pigtail that attaches to the battery. The only thing I can think of was that it was my intention to add them there, and crossed some mental wires.

My apologies for the misinformation!

 

[scottladdy]

Extra current is going to shorten the life of the headlights. No question.

How much? Dunno.

But it's still a lot cheaper than burning up a wiring harness or headlight switch.

Would that be extra current? Or would the change bring the system up to design current for the lamps?

If design current, then the life expectancy would be as designed. MTBF would be as expected. Or, am I missing something?

Thanks ...