LMC Heavy Duty Headlight Harness Water in Relay

[Rich72C10]

About a year ago I got LMC's Heavy Duty Headlight Harness, part number 36-3580 but installed it some months after receiving it. So it is less than a year I think in my truck. I likely have under 5 hours of driving time at night.

After one of my truck washes, my lights started to flicker. Then over the weekend my High Beams actually turned off my lights. I reached out to LMC stating I thought I had some bad relays, which they just reported back to me "we sell replacements". Gee, thanks but I knew that - so they don't seem to care about standing behind the stuff they sell.

Anyways, I ordered two relays but while waiting for them to get here I decided to open up the problem relay. Which was rather easy as the cover isn't really sealed onto the base. As you can see with the photos, water has gotten into the relay and made a mess of things. Do note, the only water that gets on my truck is when I wash it and it stays in my garage. So never has rain (other some very light rain) hit my truck since installing this harness.

I got the relay working again but it took me using my Relay File (what I used to clean contacts on a EM Pinball machines). When cleaning relay contacts you shouldn't just use a normal file. Well you can but then you'll damage the relay contact pads and that can cause arcing that leads to the relay decay (but so does water).

Anyways, perhaps this will help someone else.

[Rich72C10]

Got another response from LMC:

We are showing that the order W4242336 was placed on 09-02-20 meaning it is outside of our 1-year warranty that we offer on all of our parts. In order to gain a replacement relay you will need to purchase the part 36-3592.

So, that is 20+ days after the 1 year mark. I should have said something when the lights started to flicker on after washing the truck a few months ago.

Edit: Another email (which they sent out a "recall the previous replay" email).

hank you for reaching out to us,

As a one-time good will to you we will reship out a replacement set of relays for the set that has failed on us at this time. Once the replacements have been shipped we will update you with the tracking number.

[Southcity]

Where do/did you have your relays mounted on your truck, on the grill side of the firewall exposed to the elements? in the engine compartment? I can't speak to the LMC relay harness because I built my own but when I did, I used "weather pack" type relays to avoid any issue with debris, moisture etc., getting into the relays. I have mine mounted on the grill side of the firewall, exposed to all the elements including water from rain, road grime, car washes, etc., and it's worked flawlessly for years now.



https://www.summitracing.com/parts/p...CABEgKEXfD_BwE

[RustyPile]

One of the reasons I don't like car washes. Water under pressure does lots of damage. Technically, under warranty or not, the relays' failure falls under misuse or improperly installed.. You probably mounted them with the plug facing up and water got in.. It's nice of LMC to reconsider and send you some replacements.. Mount the new ones with the plugs facing down and water won't encroach..

[Rich72C10]

They are mounted inside, between the passenger fender and battery - facing down and inside the engine compartment. Who would mount any relay upside down to expose the connector easily to the elements? That would be nuts but thank you for implying that I am :p

I never go to a car wash, I use my water hose under house water pressure. I also haven't washed directly into my engine compartment. So all this water has worked its way from washing from the outside. Though I do spray directly into the grill/front of the hood. Which is where water would get to the area my relays are mounted. If I mounted the relays forward of the battery (say on the inside passenger fender) I'd get the same amount of water splash/drip. There isn't that much length I think to go anywhere else to mount the relays.

So I don't think this is a case of "misuse or improperly installed". These relays should be sealed and by me pulling the cover off, there aren't sealed (cover glued to base).

[Rich72C10]

Okay, so I decided to open up the other relay, which butts up right to the other "rusty" relay. This one was a bit harder to pull apart but not by much. There is no indication water has even gotten into this one.

Edit: This is where I have them installed, on the brace between the passenger fender and the battery.

[Southcity]

It's possible the issue may return even with replacement relays, I don't think the relays that come with the LMC harness are "weather tight". I'm basing that on the pic of the LMC heavy duty harness/relays in this thread. You'll have to keep eye on it but you could easily substitute them for the "weather pack" type if the issue returns again. Good luck!

[Rich72C10]

agreed, these aren't water tight at all. When I installed the harness, I wrapped all the plugs with electrical tape but I didn't do anything to the relays themselves. I didn't think the relay's themselves would get water in them. These should be water tight, IMO.

I am sealing these original relays with Epoxy 2-part glue. Unless the cover is compromised, no water is getting into them now. I'll keep the replacements (will also be sealed with epoxy by me) as spares.

[Southcity]

Sounds like a solid plan and hope it provides trouble free operation for you. Of course now I have to ask, what type of headlights are you running and what is your experience with your setup since installing the relay harness?

[Rich72C10]

Aside from the relay drama, I love the setup but I should have done it myself for water tightness. Just another example as doing things "easy" can bite you in your arse later LOL

As for my headlights, see this thread on Dapper LEDs, https://67-72chevytrucks.com/vboard/...ghlight=dapper

[HO455]

Originally Posted by Rich72C10

agreed, these aren't water tight at all. When I installed the harness, I wrapped all the plugs with electrical tape but I didn't do anything to the relays themselves. I didn't think the relay's themselves would get water in them. These should be water tight, IMO.

I am sealing these original relays with Epoxy 2-part glue. Unless the cover is compromised, no water is getting into them now. I'll keep the replacements (will also be sealed with epoxy by me) as spares.

Just a note the holes where the connector spades pass through the base of the relay are not water tight. In a water proof relay the base would be potted to seal those areas.
In non-water tight relays the connectors and other components are installed in preformed holes in the base after it is molded.

If the connectors look good and clean it is possible that the moisture came pre-installed from the factory.

[body bolt]

Those are called 'Bosch relays' even though the ones you have aren't made by Bosch. If they fail again try using actual Bosch relays.

[Davidf]

I purchased the harness from LMC or maybe on of their competitors, cannot remember. The relays supplied are definitely not intended for wet locations and should be mounted in a weather proof (fuse) box. Also, the small triangle brace will see water during washes and rains. I mounted mine to the side of the batter box in the "normal" rotation and all is well. The relays are cheap and probably a good idea to have a few spares on hand.

[Rich72C10]

I think the relays will be fine now that I have them sealed up with epoxy between its cover and base. Though if not, I'll break out the spares that I'll end up with and adjust the mounting location!

At the time of mounting the relays, I thought I was being clever with the location for easy access and no strain on the wiring. Hindsight is 20-20, as it always is!

[dagnabbitt]

I just purchased and received my GMC headlight relay kit from LMC. I bought it because my 72 is the one classic vehicle that I think I will drive in the winter, and winters are DARK here.

My mechanic friend is extremely skeptical of the product, maybe he is right. I know that people who are handy can simply make their own headlight kit but I bought mine because I am not that person.

[Rich72C10]

I remember when I got the kit, I wasn't all that impressed either.

Get yourself some 2-part epoxy to seal around the cover and the base. Though I popped off my covers and placed epoxy (carefully) around the base, put the cover back on, and ran epoxy around the seam.

It was real easy to pop the covers off, which is why water can get inside.

Then I'd get some good electrical tape to wrap all the connectors, then I also used over the electrical tape engine wiring tape, it's fabric like.

I think if you keep the water out, the relays will be fine but only time will tell.

[dagnabbitt]

Originally Posted by Rich72C10

I remember when I got the kit, I wasn't all that impressed either.

Get yourself some 2-part epoxy to seal around the cover and the base. Though I popped off my covers and placed epoxy (carefully) around the base, put the cover back on, and ran epoxy around the seam.

It was real easy to pop the covers off, which is why water can get inside.

Then I'd get some good electrical tape to wrap all the connectors, then I also used over the electrical tape engine wiring tape, it's fabric like.

I think if you keep the water out, the relays will be fine but only time will tell.

Thanks I will give that a try. The kit worked as intended, at least?

[Rich72C10]

yep, it sure does. Big improvement over running the power through the dash switch. Until I had relay issues, I thought the kit was the best thing since sliced bread!

[HO455]

If you're building your own or want to upgrade.

https://www.amazon.com/PACK-AMP-Wate.../dp/B074FSZWVT

[Rich72C10]

those look the good ones to me, I might update to those.

[RichardJ]

I wouldn't tape up the relay plugs. You're just going to trap the water in there. GM used those Bosch type relays with open plugs for years with relatively few problems.
You lost one relay. Doesn't seem like a major problem.
I get my relays and plugs for may different applications from the wrecking yards. Under the hood of any 80s GM auto and you will find at least a half dozen of those type relays.
I placed the fan relays in my truck in the same location you used and the headlight relays in an even less protected location on the other fender.

[body bolt]

Originally Posted by RichardJ

I wouldn't tape up the relay plugs. You're just going to trap the water in there. GM used those Bosch type relays with open plugs for years with relatively few problems.
You lost one relay. Doesn't seem like a major problem.
I get my relays and plugs for may different applications from the wrecking yards. Under the hood of any 80s GM auto and you will find at least a half dozen of those type relays.
I placed the fan relays in my truck in the same location you used and the headlight relays in an even less protected location on the other fender.

I have 50 and 30 year old Mercedes and have never had to replace a Bosch relay.

[Warrens69GMC]

Originally Posted by body bolt

Those are called 'Bosch relays' even though the ones you have aren't made by Bosch. If they fail again try using actual Bosch relays.

Never seen those style relays called Bosch. Bosch relays are usually referred to the 4 or 5 pin versions square version(s)

If you came to any store that I know and ask for a Bosch relay, you would get handed one of these.

[body bolt]

Originally Posted by Warrens69GMC

Never seen those style relays called Bosch. Bosch relays are usually referred to the 4 or 5 pin versions square version(s)

If you came to any store that I know and ask for a Bosch relay, you would get handed one of these.

I work in automotive engineering and regardless of the number of poles, we call them Bosch relays because of the form factor.

[Warrens69GMC]

Originally Posted by body bolt

I work in automotive engineering and regardless of the number of poles, we call them Bosch relays because of the form factor.

Do you refer to r134 of r1234yf as Freon then?