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Trailer Wiring Harness Installation - 2008 Toyota Sienna

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How to Install a Wiring Harness for a Trailer on a 2008 Toyota Sienna


Today we are going to install part number 118304 from Tow Ready. On a 2008 on a Toyota Sienna Mini Van. The first thing we are going to do is remove the tail lights. We will start on the passenger side then work our way over to the driver side. To remove the tail light we have to push down on this pin and pull the connector out. We will go ahead and do the same thing for the other side. The next thing we need to do is to remove this trim panel here. There are 3 of these latches we have to remove all the way across from left to right. Once we have those 3 latches removed we can now take off this back part of trim panel. You have to pry it out and lift it up at the same time and it will come loose. Now at this point we need to pull this panel away.

We do not have to take it out but we need access to get our hands in there to reach the other side of the wiring harness. Watch your hands there are some wires connected to the panel and if you pull too hard you will rip those wires right out. Thats all you need right there to get your hands in there. Might want to get something to pry it open a little more while you keep your hands in there and that is about it. Going back to the passenger side we need to take off the cover panel for the spare tire tools. Also take out the tools so that we have just a little more room to reach the back.

Starting off with the driver side we are going to take the yellow and blue wires and feed them up and pull them through the top hole. Then the tail lights will actually connect there. Now we need to run our wire down and out of the way. The next step we need to go back to the passenger side and run those lights. It is going to red for brake lights and green for running lights. What you do sneak these wires down under the panel down towards the bottom towards the converter box and 4 pole flat. The rest we can just store back in there. Now we need to run this wire up and through the plastic here. Then it can come out by the tail light and make our connection. The remaining wires we are going to tuck behind the plastic here and out of the way of the jack tools. Now you want to keep this box on the inside and we are going to run the ground wire. You want to find something that is kind of laminated in between 2 pieces of metal. So that you have more metal to run your attachment point into. What we are going to do is drill our ground point through these 2 pieces of metal here. Then we will sneak all this wire up behind it and pull it up to the hole. We are still going to take our box here and tuck it near the bottom. On a flat spot you can actually use adhesive to hold it into place. Then put it as far to the bottom as possible. Now we will pull out our 4-pole bundle and pull them out of the way. Now we can reinstall our jack tools and make sure everything fits.

While we are here you can shut this panel and then drape the harness over the edge of the bumper. We will cover that in a little more detail later. At this point we go back and start assembling our plastic components. Go ahead and push this component back into place then we will put our tracking back down. Now we can put our tail lights back together. We will start with the passenger side. Right now our install is basically complete. We will now show you how to use the harness when your plugged into the trailer. You will have the harness pulled out and draped over the back of the bumper like so. Now shut the tailgate and as you notice there is plenty of room under there with a seal. You can go ahead and pull the harness out for as much as you need. There you have it for the install of part number 118304. Which is T-One Vehicle Wiring Harness from Tow Ready. Installed on a 2008 on a Toyota Sienna Mini Van.


Info for this part was:

Employee Joe V
Test Fit:
Joe V
Employee Nicholas E
Test Fit:
Nicholas E
Employee Randy B
Test Fit:
Randy B
Employee Zack K
Video Edited:
Zack K
Employee Jacob T
Video Edited:
Jacob T
Employee Sue W
Video Edited:
Sue W
Employee Joshua S
Video by:
Joshua S
Employee Kathleen M
Video by:
Kathleen M
Employee Cole B
Installed by:
Cole B

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