View Full Version : Help! - wiring up a boat trailer and other stuff

Fred Voorhees
02-27-2005, 11:53 AM
Last Fall, in a rush, I purchased an old 14' aluminum boat that I intend on using for bass fishing on the Delaware River during the Summer months. Before the season gets going, I want to go over the entire boat and "clean it up". That entails, among other things, completely redoing the electrical wiring of the trailer. I'm looking for some direction as to how to proceed in doing same. Being that the boat is of '50's vintage, I'm assuming that the trailer is pretty much the same age, though I'm not sure of that. With that being said, I am assuming that finding a wiring harness for it might be a bit difficult. However, I plead ignorance in this area. Would it be just as easy purchasing all of the seperate parts such as the brake lights, marker lights and connectors and such and wiring from scratch? I wanted to get the trailer and boat into the garage to begin work on it soon so that it's ready when Mr. Bass decides to come out of his Winter sluggishness.

Oh and another thing, I plan on epoxiing all of the seams. Anyone have any reccomendations for this?

Jim Becker
02-27-2005, 12:12 PM
Places like Northern Tools (http://www.northerntool.com/) sell all kinds of trailering gear, including wiring stuff!

'Meant to stop by on Friday on my drive home from "entertaining" a customer, but just plain forgot to turn off Rt 202 onto Rt 31...and didn't realize it until I hit the bridge into PA! Sheesh!

BTW, I think I saw your billiard table (in black) at the Suburban Home Show yesterday. Big. Very big. ;)

Chuck Wintle
02-27-2005, 12:51 PM
What is the condition of the wires on the trailer? Anything worthwhile saving or is all corroded and frayed? I would buy a ready made harness with standard trailer connector and install that. I expect all you have on a trailer are running lights and brake lights.

Jerry Clark
02-27-2005, 1:02 PM
Just a reminder-- check and pack the wheel bearings on trailers every year-- whether you use it or not! I see a lot of trailers on the side of the road with a wheel missing! It is best to replace all the wiring and lights -- and coat all connections with dielectric material prevent corrosion. It is not a difficult job.

Karl Laustrup
02-27-2005, 1:07 PM
Well, Fred, as I used to own an auto electric repair shop let me see if I can help you. Please read through this completly so you can get an idea of what you might need.

First I would go to the local borg and get your lights and whatever type plug harness that matches what you have on your vehicle. While you are there get yourself some 14 ga. wire in yellow, brown, green and white. Figure you'll need a minimum of 20' of each. Get a roll of electrical tape and an assortment of connectors. These usually come in small plastic compartment boxes and will include butt connectors, and other types of wire ends. The butt connectors are to connect two ends of wire together and you will be using primarily these. You will also need a crimper to crimp the butt connectors to the wire. Note: Try to get lights that have a ground wire, not the type that ground to the trailer frame. Corosion will quickly render the ground connection useless and then all kinds of weird things happen with your lights.

Lay out each color wire in lengths of at least 20', or more figuring the harness will run along one side or the other. [there will be some waste of the wire once you get it hooked up]. Using electrical tape wrap the wires every 3' or there abouts [don't tape within 2' of either end]. You now have a wire harness.

Mount your lights and then beginning at the light farthest from the side you'll be running your harness, start hooking up your wires. After you crimp the butt connectors, give them a little tug to make sure the connection is good. Standard color coding is Green right turn and brake; yellow, left turn and brake, brown tail lights and white is ground. NOTE: If your vehicle has the brake lights and turn signals separate [turn signal will be yellow lens on rear of vehicle] you will need to purchase a special converter that will mount on your vehicle to convert the separate turn/brake into an all in one for the trailer. You can get the separate turn/brake lights for the trailer, but then you would have to run more wire.

As you run your wire harness to the front of the trailer, you will need something to keep the harness on the trailer frame. I don't know what you have so that will be up to you, although I would not recommend any kind of tape. It will deteriorate pretty quick going in/out of water. I use plastic tie wraps.

Make your connections at your trailer plug and tape any connections you've made with the electrical tape. Plug it in and you should be ready to go. Oh, and leave enough harness so when your hooked up and make a turn it doesn't pull out or other wise damage your wiring.

Just a couple of notes Fred.
1. Try to run your ground through the vehicle/trailer connector and ground the white wire directly to the frame of the vehicle.
2. If you can only get lights that ground to the frame of the trailer you should spray WD-40, or equivalent, on the bolts that mount the lights to the trailer after you pull it out of the water. And in that case you can eliminate the ground wire in the harness. Just hook a wire to the tongue somewhere and run the wire through the harness to the vehicle. DO NOT COUNT ON THE CONNECTION OF THE HITCH TO THE BALL A GROUND. You need some kind of wire connection from the trailer to the vehicle for the lights to work properly.
3. If you have strange things happening with the lights the most probable culprit is GROUND. That is if you have done all your connections right.

Sorry this is so long winded, but I don't know if there is a short version without having problems with your lighting and I have tried to cover every scenerio to have the job go quickly and without any glitches.

If you have any other questions let me know.

Good luck.

Jeff Sudmeier
02-27-2005, 3:56 PM
3. If you have strange things happening with the lights the most probable culprit is GROUND. That is if you have done all your connections right.

Wow! Karl, pretty much summed it up. Just wanted to add that I have had funky problems with my lights on my camper and it did indeed turn out to be the ground! It seems like most 12v wiring problems can be tied to the ground.

Steve Clardy
02-27-2005, 5:13 PM
You can purchase a KIT, even at Walmart. Has the rear lights, a flat four wire cable, and plugs for the boat and truck. That's the best way if you are to replace everything.
Just measure your trailer length to make sure the harness is long enough.

Fred Voorhees
02-27-2005, 7:37 PM
Thanks to everyone for their replies, especially Karl and his very detailed reply. Karl, I have printed out your comments and will keep them on hand for the job at hand. The trailer does have a working harness on it, however, a light here and there are either broken or not working and I just figured that for the minimal cost that would be involved, I would just use the off season time to simply replace everything and start with some dependable stuff. While I was at it, I would clean up the frame and give it a good paint job. The trailer does have the flat four connector plug so I can easily trace out the coordinating color/light scheme.

Karl Laustrup
02-27-2005, 8:44 PM
Glad I could be of help, Fred. :) As long as you have the time I think you are very wise in your choice to re-do the trailer from stem to stern. Once completed and with a little care the lights and wiring should last a loonnnnnng time.