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Optronics Wishbone Trailer Wiring Harness Installation

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How to Install the Optronics Wishbone Trailer Wiring Harness

On this flat bed trailer, we're going to install part number A20WB. This is a 20 foot, wishbone, 4-way trailer wiring harness. First, we'll go ahead and take our wire harness apart. We'll go ahead and untangle it and get it straightened out. We'll also point out the feature of a wishbone, where you have left and a right-hand side. You notice there's a green wire with a brown wire and a yellow wire with a brown wire. That carries a running light circuit to both sides.

Our yellow will go to our left side and our green will go to our right side. Now, on this particular trailer, we're going to run our wires through a tongue and we're going to go ahead and drill out a hole behind the coupler. We'll go ahead and drill a nice 16th hole. Then, install snap bushing. The part number we're using is SWC8055. Once we have our bushing installed, we'll go ahead and use a pull wire to pull our new wire harness into place. Now, we're actually using an old piece of airline tubing.

This could be any piece of wire if it can help hold its shape and still maneuver it through the tongue of a trailer. We'll go ahead and running it out to the end of a tongue of a trailer underneath. We'll go ahead and attach our wire harness to our pull wire using some electrical tape. We'll take the two lengths of wire and put one behind each other to keep it as narrow as possible and fit through the bushing. Once we have the wire secure, we'll go ahead and pull it through the tongue and out the back. Then, we'll go ahead and take up all our slack. Then next, we'll go ahead and work with our ground wire. Now, in this case we don't have a fastener that'll work with a large ring terminal on it, so we're actually going to change out the ring terminal to a smaller one.

Now, the ring terminal we're using is part number 44-5356A and we'll use a self-tapping screw. The screw we're using, uses a 3/8 nut driver on it and it's about a number 14 size screw. We got ground wire attached. Then, we'll go ahead and use some loom material. We'll be using part number 459075-1. We'll just go ahead and use that to cover up the wire, going from a 4-pull to where it goes into the tongue.

Just under 3 foot will work just fine. Maybe some electrical tape to seal up the ends. Now, push your wire into place and then secure it at the end, so it doesn't get pulled out at the bushing, we'll use a limb clamp. The limb clap we're using is part number A0500. Next, we'll go ahead and make a quick inspection on where the wires came out the tongue, to make sure we don't get pinched. In this case, we actually use a couple small quarter inch holes on each side of a tongue, to route our wires through, to keep it away from the bolt on the inside and sometimes, where a tongue is bolted to a trailer frame, it'll work like a scissor. It's a good idea to just move the wires out of the way. Working on our passenger side, we'll go ahead and route our wires along the frame components and out to our first running light. We'll also zip tie it along the way as necessary. We'll go ahead and run our wire harness to a light and there's a length of wire on it. We'll go ahead and match up to the length and mark it. Then, we'll split our wires in half to get access to the brown wire. We'll go ahead and cut our brown wire in half. We're going to use a buck connector as a junction to connect three wires together. Nail 00:03:33 One end of the buck connector, we'll take our black wire from the light and connect that to the brown wire from our harness. Then on the other end, we'll get the rest of the brown wire, going into the buck connector. The buck connector we're using in this application is part number DW05744-5. We're using a heat gun and it makes it easy to point the heat in a direction that you want. You can also use a lighter or a barbecue pit lighter, as well. Then, optionally we can go ahead and add some electrical tape to keep the bundle together. We'll use another limb clamp, the same part number, and we'll go ahead and use that to hold the wires underneath the trailer. We'll go ahead and continue running our wire out to our tail light. We'll go ahead and run it through a frame and any pre-existing mounts for the old wire. Once we get to our tail light, we'll go ahead and remove any pre-existing wires going into a tail light. Once we have our wires ran to our tail light, we'll go ahead and cut off our excess . and strip back the wires about a half an inch. Now, on our passenger's side, our wires going to be using the brown wire, of course, for running light circuit and then the green wire for left-turn signal and break signal. Now, on this particular light, the wires just push into the light itself. There's a little tab in there that grips the wire. When we're done with our passenger's side, we'll go ahead and do the same exact steps over on the driver's side. However, on the driver's side, we'll use a brown and yellow wire. That'll do it for part number A20WB. 20 foot wishbone, 4-way trailer wiring harness on this old flat bed trailer. .

Info for this part was:

Employee Jeff D
Installed by:
Jeff D
Employee Cole B
Installed by:
Cole B

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