This Old Trailer: Wiring Trailer Tail Lights

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Wiring Trailer Tail Lights Episode of This Old Trailer


In this edition of “This Old Trailer” we are going to wire up the lights on this trailer. Previously we had hooked up electric brakes and you can see, right now we have the junction box installed on there and we have wires ran for electric brakes. We have nothing for the actual tail lights themselves. That is what we are going to start on today. :30

We are going to hook up our 7-pole wiring harness with the molded connector, and we are going to hook that up to our junction box that we I installed on the frame. Inside the junction box the colors are labeled, so we will match the wires from the connector color for color with the junction box. :46

Now what we are going to do next is hook up our wires from the trailer into the junction box itself. Now there are some differences in the code, this is where you go by function not colors of the wire. Yellow is going to be the left turn on the trailer, and it is going to be red on our junction box. Right turn is going to be green on our trailer and that is going to brown on our junction box. Brown is going to be running lights on our trailer and that is going to go with green on our junction box. Now we can go ahead and secure all our connections with the hardware. All right, lets go ahead and run the wires down through the frame, back towards the tail lights. We will use the preexisting holes in the frame, and just take care when we go across the suspension components that we keep the wires out of the way so they do not get mashed between the axle and the frame itself. 1:45

Next we will go ahead and install the tail lights. We will start with the grommet, just install it in the bracket that is actually going to hold the tail light. Next we are going to install our wire harness, or also called the pig tail, into the tail light. These are somewhat keyed so you can not mess them up, they can only connect in one way. Just take time to make sure all the pins are properly lined up because it is kind of hard to push together, but if you have it perfectly straight it will go together like it is supposed to. It is a push fit, so it does not click and lock or anything. Then we can go ahead and install our light, just push that into the grommet itself. We will now start making our wire connections, and yes the wires will not match in color so we will have to go by function. We will start with our running light wire. Our trailer wire is going to be brown for the running lights, and then on the wire harness coming from the light, the black wire is going to be the running light circuit. We will go ahead and make that connection first. There is a variety of ways we could make this connection, in this instance we are going to go simple and use quick splices, but you can use a butt connector or any other type of connection. Our next connection we are going to make is for our right turn signal. That is going to be the yellow wire on the trailer and the red on the lights. Lastly, we will go ahead and make our ground connection. We will make the connection straight to the frame of the trailer. 3:28

At this point we can bundle up our wires and secure them to the frame of the trailer. Next, we will start working on the passenger side, or the right side of the trailer. We will do the same process as before, except this time we will be using the green wire and hooking it up to the red wire. The yellow wire we will just leave alone. Now with all the wires attached and secured we will put the lid back on our junction box and test our wiring harness on the vehicle. One final check of the lights to make sure everything is working correctly. Left turn, right turn, running lights, and brake lights. That finishes our install of a wiring harness and tail lights on “This Old Trailer”.


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Info for this part was:

Video Edited:
Jacob T
Video by:
Dustin K
Installed by:
Cole B
Installed by:
Hayden R

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