Re-wiring Trailer

[l008com]

About 10 years ago I replaced the lights with LEDs on my 30ish year old trailer. And I replaced the plug a few times because I'm always having problems. I crimped everything, not soldering, so it's all going bad again. The original harness also had a bunch of built in plugs, so the lights were essential modular. But ideas in the 80s don't work so good here in 2019. So my crimps are going bad, the original connections are also going bad. It's all going bad.

So I'm thinking about just replacing the whole harness. It's only a 15' boat so what maybe a 20' harness. I have a few thoughts/questions on this.

First, it seems like grounds are constantly going bad. That's almost always the problem. So rather than grounding everything to the body of the trailer, I was thinking of buying a spool of thin white wire and doing a proper grounding from each light, all the way to the plugs and ultimately to the truck. It would be a little more soldering, but the end result should be MUCH more reliable than the standard ground-to-body configuration.
BUT is there any reason I shouldn't do this? Meaning, will there be some negative electrical effect of not grounding to the body of the trailer? Like the same reason you need zink on your hull, that kinda thing?

Second, where's a good place to get a quality harness? I know "quality harness" isn't really a thing, they're pretty much all dirt cheap items. Maybe then what I'm really looking for is some way to "reinforce" the plug end of the harness so the connector and wires leading in to it don't fail?

 

[tpenfield]

I have done a similar thing to what you are planning. . . i.e. taking a trailer harness and adding some wiring to it. For each ground wire, you can/should ground it to the trailer frame. This is basically the same as grounding to the frame, except there will be the white ground wire there as well. Should be no issues.

Not sure where to get a higher quality harness. I usually add electrical tape wrap and some wire conduit in chafe areas to add some longevity. Soldering all the splices and connectors would be a good thing for longevity as well.

 

[l008com]

The grounding connections to the frame seem to have a much higher rate of failure than any other type of connection. That's why I was thinking i'd just wire the whole thing. I could always keep one connection to the body from my ground wire, and I could keep it above the launching water-line. But why "should" I ground to the body vs doing this? Is there a reason for it?

 

[Scott Danforth]

run individual grounds to each light

i do have a grounding ring lug to the brake head for the reverse solenoid because that is not a 2-wire solenoid.

no other reason to have a chassis ground on a trailer if you have individual grounds to each bulb.

I always rewire any new to me trailer.

I buy a 100' spool of trailer wire I do not split the wires, I run a full branch down each trailer frame member (simply do not use the one wire on each side for the opposite turn signals) that wire get sealed with a bit of heat shrink.

I always non-insullated butt splice, solder and then seal with epoxy lined heat shrink

where all the wires come together, I pot that bunch of heat shrunk connections with flexible potting compound (its about a 1-1/2" diameter x 6" log of elastomeric potting compound when I am done)

My lights would work if you removed the trailer from around them

 

[l008com]

I have no brakes, only lights. So yeah it should work good it sounds. Can you tell me about this epoxy lined heat shrink? Sounds very useful. I do have some of those sealing heat shrinks with low temp solder in it, but i'd like an even better seal for the connections that are going to get dunked regularly.

 

[dingbat]

The biggest thing you can do to increase the life expectancy of the system is get rid of the cheap trailer wire.

The stuff is junk. Cheap jackets and untinned wire amongst other things. Doesn’t matter what you do, what kind of heat shrink you use, black wire disease will get you every time with that $rap.

I run 18-2 marine duplex wire to each light and terminate with ring connectors in a tongue mounted junction box on the tongue.

While I’m at it, I always swap out the cheap 4/5 pin connectors for a 7 pin RV connector. Better connector, better wiring, better all around solution.

Not a fan of soldering in damp environments. What can go wrong when you mix lead, tin, copper and steel covered in acid together?

Proper cleaning of the joint before and after soldering is paramount for long term survival of a connection. They’re is a reason why we avoid making solder connections in the field if at all possible.

Use Ancor heat shrink butt connectors for all terminations. Add a bit of adhesive lined heat shrink on top for good luck if you like.

 

[ahicks]

I like running ground wires with the rest of the harness too. Have learned using the frame to ground is not a good plan when thinking long term. I would not go to the trouble of a complete rewire unless using quality lights either. Today's LED's are an absolute must for a do it one time and forget it install.

Last, I generally make my own harness, starting with 4 wire flat ribbon wire. It doesn't need to be anything real fancy. Have found the same with the 4 wire plugs. Installed properly, they'll last a long time as well.

 

[Scott Danforth]

I have no brakes, only lights. So yeah it should work good it sounds. Can you tell me about this epoxy lined heat shrink? Sounds very useful. I do have some of those sealing heat shrinks with low temp solder in it, but i'd like an even better seal for the connections that are going to get dunked regularly.

seriously, its available everwhere marine wire is sold. I get mine on amazon because I work long hours and amazon delivers.

 

[matt167]

My boss bought a 3 year old dump trailer and none of the lights worked right. I terminated grounds at each light, put a new plug on it and put in brand new LED lights, and it came to life

 

[MTboatguy]

I make my harnesses out of a 100 foot rubber coated extension cord now a days 14 gauge cut to length, solder and crimp the ends with dielectric grease on them. They last much longer and with the solder, and crimped butt joints they hold out. As the cord I pick up is a two conductor, it gives me two wires per side, one for power, and a ground wire. The wire is inside my trailer tube frame I don't have to go deep in at the ramp to launch my boat. So far it has worked out quite well on my boat trailers, no water invasion, no corrosion and the grounds hold up quite well. I also use the epoxy shrink wrap on my harness and use a 7 wire RV plug

 

[82rude]

Im certainly not an expert at trailer wiring.It seems that everybody has their own thoughts on this.Most though would agree to not patch up somebody elses work but rip it out and do it from scratch.As for lights id never consider anything but led now.I bought a set off of amazon for a very reasonable price and they are well sealed and made.

 

[MTboatguy]

The wire I am using that is rubber coated is the same wire we use to do outdoors stuff to hold up to winter around here, for like heat tapes and outdoor plugs, it is tinned wire and rubber not vinyl coated. It holds up very well and stays flexible.

 

[l008com]

So I was browsing around looking at trailer harnesses. There are wishbone harnesses, which are just what you need for a boat trailer. It will make it much easier to install, with far fewer connections to make. I've also seen a few harnesses that feature a full length ground. That would make my no-body-grounding idea very easy to implement. But alas, I have not been able to find any harness that is BOTH a wishbone style, and has full length ground(s). Anyone know where I can find something like this? A harness configured like that would make it so easy to install. 2 solders at each light and I'm done! Well I guess three at the brake/tail lights but still, far fewer connections means less time working on it and fewer points of failure. I'm going to keep looking for one but if anyone knows where I can find one, definitely let me know!

 

[bigdee]

Harbor Freight has a 25' harness that includes a 25' white ground wire in the harness. 14 gauge wires too.

 

[l008com]

It doesn't appear to be a "wishbone" style harness though so you'd still have to do lots of extra splicing.

 

[bigdee]

It doesn't appear to be a "wishbone" style harness though so you'd still have to do lots of extra splicing.

HF is a wishbone harness that is what I used on my trailer....no splices.

 

[Tycer]

I’ve started using the low temp solder/heat shrink butt connectors.

 

[l008com]

I’ve started using the low temp solder/heat shrink butt connectors.

I actually do have these but because the trailer doesn't just get wet, it literally gets dunked regularly, I'm going to attempt to make even stronger, even more waterproof connections than that.

 

[l008com]

HF is a wishbone harness that is what I used on my trailer....no splices.

Really? Does the full length ground also split in two, one for each side? Even if not, it's sounding like that harness is as close as i'm going to get to what I'm looking for. I'll go pick one up and see how it looks.

 

[l008com]

It only JUST occurred to me, I don't even need a split "wishbone" type of harness. If it's long enough, I can just loop around like a question mark shape I'm not sure if 25' will be quite long enough to do that, hopefully it will be.