Trailer Wiring Harness Installation - 2015 Ford Fusion

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How to Install a Trailer Wiring Harness on a 2015 Ford Fusion


Today in our 2015 Ford Fusion, we're going to review and install the Tow Ready T-One Vehicle Wiring Harness. Part number 118574. Now, to use your new 4 pole trailer connector, simply open up the rear trunk, the spare tire cover and we'll pull it out from where it's stored next to the spare tire. Now, we can simply run it out and over the threshold staying away from the trunk latch but knowing that the weather stripping is thick enough that we can simply close the rear trunk on our 4-pole connector. We'll run it down to our e-trailer accessory and then once we're finished, we can simply roll it up and store it down with a spare tire making it a really nice feature that it stores inside the vehicle and outside of the elements that can cause wear and tear on our 4-pole connector. Next, I'm going to show you how you install the Tow Ready 4-pole trailer connector. Now, to begin our install, we're going to open up the rear trunk and remove the spare tire cover.

Next, we're going to remove the rear threshold. No to remove the rear threshold, we've got 2 push pin fasteners. One on each side. To remove the push pin fasteners, we're going to get underneath to it, pop it out. Now you can use a flat-blade screwdriver or an interior trim panel tool.

Makes it pretty easy. Now the fasteners out of the way, we're just gonna gently pull up on the corners releasing any fasteners underneath. Now ultimately we're trying to gain access here behind the driver's side and passenger's side tail light assemblies so we need to remove the carpeting. The 2 tow hooks here, top and bottom, hold the carpeting in place so we'll go ahead an the tow hooks by just spinning the off the metal stud. We're then able to pull the carpeting out and back gaining access behind it. Now, with the carpeting out of the way, to get our tail light out, we need to remove the 2 nuts that secure it.

We'll just set those aside for now so we can reinstall them later. Now, we'll go ahead and take our tail light out. Be careful not to break off any of the alignment tabs underneath as you remove it. To assist, you could use a flat-blade screwdriver or we just got a plastic little pry tool here to help get underneath and pop it free. Here, you can see the alignment tab underneath.

We'll go ahead and disconnect the tail light assembly from the manufacturer's wiring. There's a locking tab here on the connector. We'll press it and then release it too from each other. We're going to set our tail light aside. Now with the driver side done, we're going to move over the passenger's side and repeat the same process. Now we've gotten ahead and removed the tail light assemblies, we'll access the manufacturer's wiring. Here, there's a grommet that leads to the outside wiring harness that connects the tail light. We're going to remove the grommet by pulling it inside gaining access to it. We're going to cut a slit in the grommet and feed our T-connector outside to the manufacturer's tail light connector. To cut a slit in our grommet, we're just going to use a pair of side cutters. I just need a large enough slit that we can slide our wire into it once it's been in place. Now, to assist in running our wire into place, we're going to use a pull wire which could be a stiff piece of wire. In this case, we're going to use a piece of air tubing. I'm going to roll it down to our grommet hole. Once we get the pull wire in place, we'll take the yellow and brown wire T-connector, attach it to our pull wire using some black electrical tape and then pull it into position behind our tail light. Once we get the yellow and brown wire T-connector behind the driver's side tail light assembly, we'll go ahead and remove our pull wire and plug one side into the manufacturer's connector that goes to the harness and the other side, will go to out tail light assembly. Once we have our T-connectors in place, we can go ahead and reinstall our tail light assembly. We'll put our tail light back in place and then re-secure it with the 2 fasteners. Now with my tail light assembly in place, we'll go ahead and take the yellow and brown wire, feed it into the slice we cut in the grommet and then reinstall the manufacturer's grommet. Now once I've got my grommet back in place, I like to go and take one of the zip ties provided with the install kit and secure the yellow and brown wire connector here to the manufacturer's wiring. Now, with the driver side done, we'll take the green wire T-connector, run it over to the passengers side and repeat the same process. All right, now with the grommet reinstalled, we'll go ahead and secure the wiring here and the green wire as we route back over the driver's side. Take the red wire from our converter box and strip it back. Then we can take extra length of power wire provided with our install kit and secure the 2 together using the yellow butt connector provided. Simply slide the butt connector onto our power wire and crimp it down. Then we'll go ahead and take the extra length of black wire provided. Put it at the other side of our butt connector and crimp it down. Now, I recommend you go and wrap up this connection point with some black electrical tape to help keep it clean from dirt, dust, debris and moisture. Next, we're going to mount the converter box. To mount the converter box, we can remove the 2-way adhesive from the backside and attach it to a clean flat surface, preferably sheet metal. Note, there is also a pre-drilled hole here with a a tab that you could use a self-tapping screw to secure it to the sheet metal also. I want to go right here below the driver's side tail light assembly. It's a good location for our converter box. Next, we'll take the white wire from our converter box. It's got the pre-attached ring terminal. This is going to be the ground wire for our converter box in our 4-pole trailer connector. We're going to attach it here to the sheet metal using the self-tapping screw provided with the install kit. Note, I recommend you find a location where the sheet metal doubles up just like this one so you get a more secured route. Next we're going to take out power wire and we're going to attach it here to the manufacturer's wiring as we route it forward. Now that it's secured here by in the carpeting, I'm going to go ahead and cut-off the excess from the zip ties to clean up my install look. We'll go and slide the carpeting back in place as we route the power wire forward towards the grommet behind the driver's side rear seat. Here we have the manufacturer's grommet that we're going to route through. Using a utility knife, I cut a small slice in the grommet and feed our power wire through it. Now, this grommet's got 2 layers to it. The nose has got a larger slice here in the top. I'm just going to pull that back so I can gain access to the layer underneath. Now once we have the slice cut in the grommet, I go ahead and take my power wire and route it through it. We can go ahead and start re-installing the rear interior. Note, as we put our threshold in place, our 4-pole connector is just going to run out from underneath of it. Now, we've got a power wire underneath the vehicle, we'll go ahead and route it up towards the engine compartment. Keep in mind when routing your wires, stay away from any moving components such as steering or suspension or excessive heat such as the exhaust. I'm also going to remove this guard here on the bottom so that I can route my power wire underneath it. Note, as we route our power wire, we're also going to secure it as necessary with some zip ties. Now, just like we did for the rear tail light wiring, we can route a pull wire down through the engine compartment along the fire wall. We can gain access to it here underneath, take our power wire, attach it to the pull wire and then pull it up through the engine compartment so we gain access to it at the top of the engine bay. Now, we're finished routing our wire underneath. I'm going to go and cut these ends of our zip ties to clean up the install look and reinstall the under body panel. Now move underneath the hood where we pull our power wire to the top of the engine compartment. Now just use a zip tie to secure it. Now here at the top of the engine compartment, we need to install an inline fuse holder and ultimately attach to the positive battery post. To install an inline fuse holder, we'll first cut it in half, strip back both ends, attach out butt connector and ring terminal. Now with my fuse holder prepped, we'll go ahead and cut up the excess from the power wire that we routed, strip it back and add it to the other side of our butt connector. Now once we've finished this connection point, we'll go ahead and wrap it up with some black electrical tape just like we did our connector at the back of the vehicle. Now, we're ready to go ahead and put the ring terminal onto the positive battery post. However, like this one, some of the positive battery post nuts are not designed to come all the way off so what we're going to do is back up the nut. Now, we've created space for our ring terminal. I'm going to cut a small slice in it with a pair of side cutters just large enough to slide over the positive battery terminal post bolt and then tighten down the nut. Now once that's nice and tight, we'll go ahead and reinstall the positive battery post cover, route our fuse holder around here to the manufacturer's wire or we can take a zip tie and secure it. Note that if it's going to be in a difficult area to get to, you can always go ahead and remove the cap and install the 10-amp fuse provided with the install kit before you secure the fuse holder. Now with everything installed I'll go ahead and cut up the excess from the zip ties to clean up our install look. Now with everything installed, let's go and test our new 4-pole connector. We'll put the ground plant on our white wire terminal, testing the brown wire terminal for our running light circuit, the yellow wire terminal for the driver's side turn signal and brake, then the green wire terminal will be the passenger's side turn signal and brake. Now we know our 4-pole harness works. We're ready to hit the road. There you have it for the Tow Ready T-One Vehicle Wiring Harness with 4-pole trailer connector. Part number 118574 on our 2015 Ford Fusion. .


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