Trailer Wiring Harness Installation - 2008 Ford Edge

Installation of a Trailer Wiring Harness on a 2008 Ford Edge

Today on this 2008 Ford Edge we are going to be installing wiring harness 118551. We are at the rear section of the vehicle, we are going to locate the ports that we will be plugging our wiring harness into. The ports are located directly behind the tail light assemblies on both the driver and passenger sides. The first thing we want to do is go ahead and remove both tail light assemblies. You can do so by removing the two screws that are holding it into place on the inboard side. Then you want to take it and gently rock back and fourth because we do need to release the outboard side clips as well. :29

With that removed the middle port here is the one we are going to be using for our wiring harness install. Our wiring harness is actually going to be routed from the inside of the vehicle, out through this grommet where it is going to make a connection to the tail light. What I am going to do is take the tail light and unplug it from all three of the ports and set it off to the side. We want to repeat that procedure for the passenger side tail light as well. Then we will move to the inside of the vehicle where we are going to start removing the interior pieces. :57

Inside the vehicle we are going to start by removing the floor covering. Next we are we are going to remove the rear threshold piece. There are clips that are holding it into place along the top side here. Like the tail light we are going to rock it back and fourth until those release. Next we will remove the Styrofoam supports, and finally we will start removing the interior panels. We basically need to remove it far enough to gain access to the grommet that is feeding to the tail light assembly. I am going to be using a rivet removal tool to pry that back and release the clips. You want to do that for the passenger side one as well. You just want to take our wiring harness and start feeding it into position. Over here on the driver side we want the ports with the yellow and brown wires on them. Again, what we are doing is feeding them from the inside, out through this grommet here where we are going to make our connections. We do want to pop this grommet out and make a cut in it so the wires can pass through. I am going to next take the ports and route them behind the panel and out through the grommet. You just want to pass the wires through that slit in the grommet we made and then we can put the grommet back into position. Next we can plug our harness in line. Again, we are plugging into the middle port from the tail light assembly. The other side of it is going to go in the back of the tail light assembly. At this point we can connect not only to this port, but to the other two back into the tail light on the driver side and put it back into position. 2:19

Moving back to the interior of the vehicle, if you follow back the wires that we just plugged into the drivers side, you will see we have a loose white wire with a ring terminal on it. This is our ground wire. If you look to the interior here, up at the top side, there is a grounding point. We are just going to put our ground onto there. From there we can reinstall the driver side panel. Next, we can take our passenger side ports, this is the one with the green wire on it, and route it across the rear threshold area here, cross through the interior panel and out through the grommet. Just like we did on the driver side. Like we did on the driver side, we are going to plug it in line and reconnect our passenger side tail light. Then we will come back inside and reinstall our passenger side interior panel. The next thing we are going to do is take the red wire and attach it to the large lead of black wire that is provided with the wiring kit. This is going to be our power source, we are going to pass this below the vehicle and route it up to the battery where we are going to connect to the positive terminal. We are going to make this connection now. To do that we just want to strip back some of the jacketing and also strip back some of the jacketing on the black wire. Take the butt connector and the wire into one end and crimp it down. Take the red wire and it on the other end. Then just take some electrical tape and tape the connection up. This large black lead of wire, we need to get it underneath the vehicle. Where the spare tire is mounted here, if we follow forward there is an existing grommet here which I have already popped up. We can use this to route our wires through. It will not only provide a good spot to do that, but it will also help us bypass the exhaust system so we do not have to worry about the wire hitting it. I am going to cut a little slit in the grommet to pass the wire through. Over here on the interior panel what I want to try and do is try and hide the wire as much as possible because we are going to have to put the stryofoam pieces back in. I am going to pop this section of panel up and route the wire behind there. 4:36

Before I feed it through the grommet there, I am going to go back here to the modulite box and on the backside of it I have double sided tape. I am going to take and adhere it to the inside of the vehicle. With that mounted into place I am going to put the push rivets back into the interior panel here. And I am going to take my black wire and feed it through the hole in the grommet and down underneath the vehicle. With the wire pulled all the way through,we can push our grommet back in. It is a good idea to take some of the provided cable ties and secure the green wire out of the way. Then we can start installing the interior of the vehicle. Now that we have the interior reinstalled we can go underneath the vehicle, locate our black wire, and start routing it up front. When routing the wire you want to make sure you avoid any possible hot spots of pinch points that could damage the wire. Now that we are up to the engine compartment, what I have done previously is take a light gauge piece of wire and routed it down from the battery area, down underneath the vehicle so I can take and attach my black wire to it and use it to pull it up into the engine compartment. At this point I want to make our connection to the battery. As you can see we have two posts here. I am just going to use this one here and you just want to take to cover off there. Next we are going to take the fuse holder that is provided with the installation kit and cut this loop in half. The one end is going to connect directly to the battery and the other end is going to connect to the black wire that we routed from the back. Again, we want to strip off some jacketing off each end. To the one end we are going to add the ring terminal that will connect to the battery and hold off making this connection over here. Connect the ring terminal to the battery and take the other end and gauge how much black wire we actually need to make our connection. Since we have plenty left over I am going to shorten that. We will strip off some of the jacketing on the black wire and add the provided butt connector. To the other end of the butt connector we will add the fuse holder. You want to again, put some electrical tape around the connection and finally take the 10 amp fuse and put it in the fuse holder. From there our installation is complete. That will conclude the installation of wiring harness part number 118551 on a 2008 Ford Edge.