Started By
Message

Boat trailer wiring questions

Posted on 6/18/25 at 12:08 pm
Posted by Major Dutch Schaefer
Location: Classified
Member since Nov 2011
38018 posts
Posted on 6/18/25 at 12:08 pm
So I went to use my trailer today and the starboard/passenger side lights would not work - running lights, brakes or turning. I checked the plug on the vehicle and it was fine.

I noticed the wiring on that side was sort of brittle. The trailer does sit outside without the boat on it and that side does get most of the sun. It gets used about once year when I pull my boat out for maintenance. I was able to splice in some pieces in the brittle area to get the lights working. As such, I guess I am going to go ahead and just rewire the trailer.

Questions, what are you guys using for wire? Are you just using the standard yellow/green/brown 18 awg trailer wire? Do you suggest I use a heavier wire? How about connectors? I have just been using everyday waterproof butt connectors. Does anyone run there wires through a protector? Mine are just currently zip tied to the trailer. Any and all suggestions appreciated. You guys often come up with some good ideas.

Posted by Mister Bigfish
Member since Oct 2018
1220 posts
Posted on 6/18/25 at 12:16 pm to
Get butt connectors with heat shrink built in. Crimp, heat shrink, then I add a layer of liquid electrical tape to each connection.
Posted by DownshiftAndFloorIt
Here
Member since Jan 2011
70886 posts
Posted on 6/18/25 at 12:18 pm to
Anything marine or marine-adjacent, I use tinned marine wire (anchor) and usually the wirefly marine shrink connectors from Amazon. Those aren't the best value but are decent and easy to get.

I did my trailer with anchor duplex 18/2 marine cable. Chicken lights and running lights all junctioned together at the tongue with a small junction box and terminal strip. Deutsche connectors at the back lights so I can easily swap them out. If its all LED, 20ga would probably be plenty good.
Posted by geauxtreauxjans
???????
Member since Oct 2005
608 posts
Posted on 6/18/25 at 1:03 pm to
Get you 2 pieces of #12/2 copper wire with the ground (regular house wire). One piece for each side of trailer. Run the ground all the way to the back and seal connections real good. Will never have that problem again.
Posted by DownshiftAndFloorIt
Here
Member since Jan 2011
70886 posts
Posted on 6/18/25 at 1:15 pm to
quote:

Get you 2 pieces of #12/2 copper wire with the ground (regular house wire). One piece for each side of trailer. Run the ground all the way to the back and seal connections real good. Will never have that problem again.


Don't do that. That's way the wrong wire for this application. It'll work, but the jacket isn't typically meant for UV exposure and 12awg is wayyyyyy overkill for the load.

Follow my advice above for trouble-free water proof trailer wiring.
Posted by Major Dutch Schaefer
Location: Classified
Member since Nov 2011
38018 posts
Posted on 6/18/25 at 1:23 pm to
quote:

a small junction box and terminal strip


Got an image or a link to what you used for this?
Posted by DownshiftAndFloorIt
Here
Member since Jan 2011
70886 posts
Posted on 6/18/25 at 1:38 pm to
I had some industrial stuff laying around. Not worth doing it exactly like mine unless you have that kind of stuff.

Just use this, it's the easiest thing. I haven't used this exact kit myself before but I would have no issues with spending your money on it.

LINK

Alternatively, Haldex makes the stuff that my buddy used to use on big truck trailers, and its what he uses for his personal stuff.

LINK

Get that, run an independent pair or triple or 4 conductor (depending on what you have exactly) to each light, put a proper heat shrink ring terminal on the end, and connect it in there. Mount it on the tongue, seal it all up nice and tight, and don't worry about this stuff anymore.

If your trailer doesn't have electric brakes, you can get rid of those wires and jump two posts together for more ground or hot terminals again, depending on what all you have.

This also gives you the option to get reverse lights on the trailer if you have a 7 way plug on the truck, which is SUPER handy to have.
Posted by Clyde Tipton
Planet Earth
Member since Dec 2007
40501 posts
Posted on 6/18/25 at 1:46 pm to
quote:

You guys often come up with some good ideas.



Don't pull your old wires until you have them taped to your new wires. That removes and replaces the wiring in one smooth move.

I made the mistake of pulling the old stuff out first and it was a pain in the butt to run the new wiring.
Posted by geauxtreauxjans
???????
Member since Oct 2005
608 posts
Posted on 6/18/25 at 2:23 pm to
Your opinion but facts are facts. I did this to my trailer 30+ years ago. It sleeps outside and I fish salt water. Have NEVER had a lick of trouble but hey, to each their own.
Posted by DownshiftAndFloorIt
Here
Member since Jan 2011
70886 posts
Posted on 6/18/25 at 2:35 pm to
You've got the best or most unused trailer ever built if it survived Louisiana for 30 years.

This isn't an opinion. It's a fact that Romex is not the right wire for this application.
Posted by geauxtreauxjans
???????
Member since Oct 2005
608 posts
Posted on 6/18/25 at 2:53 pm to
Well I would be happy to show you the trailer and the lights that work on it. You sound like a typical bullshite salesman that is trying to sell someone something they do not need. Romex may not be the best but it works and have proof that it does work. I had some romex laying around after a house rewire and did the trailer. A nice solid conductor rather than a stranded conductor. You have your opinion and I have mine. That is what the OP wanted.
Posted by DownshiftAndFloorIt
Here
Member since Jan 2011
70886 posts
Posted on 6/18/25 at 3:17 pm to
quote:

You sound like a typical bullshite salesman that is trying to sell someone something they do not need


I'm not sure how you arrived at this conclusion. Everything I have suggested is based in good marine industry wiring practice.

You're the one who sounds like a Romex salesman right now.
Posted by AutoYes_Clown
Baton Rouge, LA
Member since Oct 2012
5332 posts
Posted on 6/18/25 at 4:28 pm to
quote:

A nice solid conductor rather than a stranded conductor.


I thought solid core is a no-no with vibration.

EDIT: Im willing to bet in 12 months, wireless trailer lights will be all the rage.
This post was edited on 6/18/25 at 4:30 pm
Posted by speckledawg
Somewhere Salty
Member since Nov 2016
4254 posts
Posted on 6/18/25 at 7:06 pm to
EDIT: Im willing to bet in 12 months, wireless trailer lights will be all the rage.

I've already seen ads for this and thought about it, since I need to re-wire mine.
Posted by KentuckyArcher
Slidell
Member since Aug 2012
162 posts
Posted on 6/18/25 at 10:30 pm to
Get 2 extension cords from Harbor freight. Run them down each side.
Posted by Major Dutch Schaefer
Location: Classified
Member since Nov 2011
38018 posts
Posted on 6/20/25 at 9:46 am to
Anyone ever to homerun wiring on the trailer? That is run an individual wire to each light and connect them together at the front of the trailer. Just thinking outside the box as I have done homerun wiring with some residential stuff.
Posted by DownshiftAndFloorIt
Here
Member since Jan 2011
70886 posts
Posted on 6/20/25 at 9:55 am to
That's what youre doing with a junction box at the tongue and dedicated conductors to each light.
Posted by Major Dutch Schaefer
Location: Classified
Member since Nov 2011
38018 posts
Posted on 6/20/25 at 10:38 am to
quote:

That's what youre doing with a junction box at the tongue and dedicated conductors to each light.


So, I have two little running lights on each side of the trailer in addition to the rear running light. You would suggest a separate wire to each running light as opposed to splicing to each light with one wire?

I did go ahead an order the junction box you recommended.
This post was edited on 6/20/25 at 10:40 am
Posted by DownshiftAndFloorIt
Here
Member since Jan 2011
70886 posts
Posted on 6/20/25 at 11:09 am to
I'd run a dedicated chicken light wire down each side and splice them all in to that. That way a problem just knocks out one side of chicken lights and not the critical stuff in the back. I never found a good cheap gang splice that I liked, so I just use those lanky 3 way pinch on connectors for this.
Posted by Major Dutch Schaefer
Location: Classified
Member since Nov 2011
38018 posts
Posted on 6/20/25 at 12:31 pm to
quote:

so I just use those lanky 3 way pinch on connectors for this.


Are you using these in the image below? I have always used waterproof butt connectors as I back the boat trailer into the water.


first pageprev pagePage 1 of 2Next pagelast page

Back to top
logoFollow TigerDroppings for LSU Football News
Follow us on X, Facebook and Instagram to get the latest updates on LSU Football and Recruiting.

FacebookXInstagram