NOOOO!!!! Never use Scotchlocks. Scotchlocks are quite possibly the worst electrical connector available today. They are quick and simple but if your trailer ever is towed over wet road, they will lead to internal corrosion in the wiring that will create gremlins that many factory trailers seem to have.

The best connection method is uninsulated crimp connectors and double wall heat shrink tubing for insulation. The double wall heat shrink is the stuff with glue inside of it that liquifies when you shrink the tubing and bonds to the wire. Make sure your crimps are on clean/bright copper and seal up the connector to keep moisture out.

 

I think someones sarcasm detector needs calibration ;-)

 

Possibly but a complete newbie could read that statement and believe it. Scotchlocks need to be eliminated from the collective human experience and their inventor needs to be tarred and feathered and forced to go around the world and replace each and every one of them that have ever been installed with proper electrical connectors.

Yeah, I really don't like Scotchlocks.
Now that I have vented my spleen on this topic, I will crawl back under my rock.

 

I don't like using crimp connectors, especially in a car electrical circuit. I solder connects whenever possible and then cover with the glue inside type shrink tube.

I wire industrial control systems so I literally cut and terminate hundreds of wires almost daily and in my control panels I only use crimp connectors if a component requires them. Butt connectors? I totally refuse to us them for anything. To paraphrase Red Green, "They're called "Butt Connectors" because they're butt ugly"

Here's a sample of the projects I get in my shop so a seven wire circuit doesn't bother me.

 

Before I got promoted into an admin/management role, I used to maintain stuff like that. Your work looks fantastic. I wish the cabinets I had to work in were as well laid out.

 

This is a work in progress, after it's been tested and before it's shipped it will look a lot better. Nothing goes out of my shop that isn't 100% perfect.

 

I purchase the heavy duty 7 conductor RV trailer cable, so that will determine the wire color.

You need to install the plug on the correct wire end or it will be a real pain to align the wires to the plug.

 

My 02 Dodge came from the factory, factory tow option, with one and I bought one to keep in my pickup just is case as I wired it for the 7 flat as that is when my car trailer has and the car clubs enclosed trainer.

I was going to sat WTH you talking about but I see my meter needs adjusting too
For the newer trucks that have a frame rail harness to tail light harness plug in the left rear corner like my 81 F100 there is a Tee connector you can buy.
You unplug the 2 harnesses and plug the Tee harness in so no cutting or "scotchLok's".
Now it may come with a flat 4 on the end just cut it off and wire it into the flat 7 plug along with a good size ground wire, 12 volt power and electric brake wire.
I cant remember if there is a back up wire on the Tee if se it was wired in to "other" as none of my trailers have back up lights.

I thought the cable you bought be the foot?
Is this going into a junction box that all the trailer light wires come back to up on the "A frame" or goes all the way to the rear of the trailer and you will break out the wire to get to the other side lights? I dont know if you can buy the cable with the plug already molded on or not?

I have always gone by the SAE wiring, the cheap light wiring kits for boats go by this color code too and has always worked for me.
Thing is if the cable you got has the plug molded on I would then plug it in to the puller and test out the wire colors and write them down this way if different that how the trailer wire colors are you can cross them over.
I also test all the wires before making the permeant connection. This way you dont have to cut everything apart and start over.

BTW if your trailer uses a car battery for a lift jack or winch and use it for the breakaway brakes and you charge said battery off the puller be careful if the battery goes bad and you leave the puller & trailer plugged together as you can end up with a dead battery on the puller. Dont ask how I know this (it was not my trailer and did not know battery was bad)
Yes this has all be fixed not to happen again.
Dave ----

 

Clearly you guys don't understand. Wire color is just an overrated suggestion.

 

I've seen control panels like this and the customer expects you to sort things out and make the machine run. I also like when the customer hands me the original drawings from twenty years ago, the revised drawing with additional components installed ten years ago along with the pencil drawing on a frazzled piece of notebook paper with scribbles of additional work done five years ago. Oh yeah, all the wires covered in oil and half of the wire labels laying in the bottom of the control panel.

 

Most building construction contracts include “as built” drawings that are supposed to reflect all of the changes and “adjustments” made through the project. Care to guess how accurate they usually are, if you get them at all?

 

Years ago I worked with a guy I went to high school with and we had been working at the city bus garage for about 10 years. He was color blind and one time he called me over to a bus he was working on and asked " is this wire pink or green?" I'd always say " what color do you think it is?" He was a good sport as a bunch of us would give him a hard time. I'd ask him things like if you cant decipher between green and red, does my red 56 look the same as green grass? Then the guys would start laughing and he'd tell me to F off then laugh.

 

And you have to push the cabinet door shut to get it to latch, and that is when a wire comes loose. This really happened to us.

 

Just one? Yeah right....

 

I buy the cable by the foot and usually make the break near to where the tongue transitions to the main frame.
When making my own trailers, I weld 1/4-20x1/2 bolts down the frame rail and across where the axles are to attach electrical Mineralacs and then install 3/4 emt conduit to run my wires.