Trailer Wiring and Light Replacement Demonstration

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Demonstration of a Trailer Wiring and Light Replacement

Today were going to be replacing the wiring on this trailer. Well be replacing a 4 pole flat, as you can tell this one is pretty beat up and worn, so it has to be replaced. Were going to cut this wire off and were going to replace this brown wire also. Were going to cut this loose and pull the rest of our wire through, on this trailer here its pretty open so we can reach the wiring. Just in case though, if your wiring was run in conduit and youre replacing it, dont pull all of this out yet. Well actually tie on the new wires and use these wires to pull them through. Were going to cut off all of this old wire here, and were going to take off this old light too. I would like to point something out on this 4 pole flat, youll notice theres actually 5 wires coming out of it. Whats happening is on the inside of this pin, which is for the running lights, has two wires coming out.

The reason for that is we can split the running light circuit to both sides of the trailer. Mainly thats used on boat trailers and other light duty ones. Whats nice about that if you have a running light on the side, chances are your running wire right next to it. You can tap into your wiring without having to make a wire go all the way across. It basically provides a short cut. This case were going to run it all the way on one side and jump over since we have a small trailer and no running lights. Now were going to tape our new wires to the old ones and pull it through the frame. It doesnt take much, just enough to make it smooth so it doesnt snag anywhere. Now we simply pull the wire through. Before we pull everything through, were going to make sure we have enough leader to hang out. This unit comes with a pre-wired ground wire so were going to leave it at its maximum length and this is where were going to ground it at and well have a good idea of how much slack we need to leave. At this point its a good idea to tape up all the wires together that way it will keep them from getting tangled with anything else. Since we have our ground here were going to ground it but before that were going to take this loop off for a smaller one. Since we have an existing ground that works pretty good, well use a smaller screw. Always give it a twist when you crimp it down it will make a nice tight fit. Well re-install our screw but first well put a pit of dielectric grease on there to help protect it a little bit, electricity still flows on the ground and the less rust the better. Now we can pull the rest of our slack out.

We have our lights pulled over to the left hand side, were using the yellow and the brown, yellow for left turn. We need to cut this wire to length about 1/2 to 3/8 inch. The wires then get stuck inside here theres a little strip in here that pulls against it and when you pull it back it catches so it cant come out and makes electrical contact. You bottom out the plastic and give it a little bit of a pull back and it catches. Same thing with the left turn signal. If you notice theres two holes side by side here. You could actually jump another wire from this hole here to another light, so it acts like a miniature junction box. This little channel here hides the wire so when you push it up against your frame it wont get mashed. Your light gets installed just like that. Before we bolt on our light were going to clean this area out where the holes are that way it makes a good metal to metal contact with no rust and corrosion. You can use a file or scrape it if youre in a hurry but if you can use something more abrasive. You dont have to get these super tight, just snug them down and theyll be fine. Again were going to use the old wire to pull the new wire through. Now were back on the right side of the trailer and well do the same thing, well run the wires and install a new light. Now well install our wiring, green for the right turn and brown for the running light. One more final touch will be to run some loom clamps to the wire to keep it up closest to the bed. It doesnt touch anything, but its better to keep it out of the way. At this point well reassemble our trailer and test out the lighting. We have our trailer wired up, lets give it a test run. Notice we didnt connect our truck to the trailer so we can make sure our ground wire is working. Its not a good idea to ground through the ball because it can be intermittent from bouncing around going down the road. First well test the running lights then the turn signals, then the brake lights. Well do this for both sides. There you have it for our install of our trailer wiring harness. We used part # 475550, 440-L, and 440.

Trailer Wiring and Light Replacement Demonstration

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Demonstration of a Trailer Wiring and Light Replacement

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