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Trailer Wiring Harness Installation - 2013 Mazda CX-5

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How to Install a Trailer Wiring Harness on a 2013 Mazda CX-5

Today on the 2013 Mazda CX-5, we're going to install part number C56011 from Curt. Now, our wiring harness installs right behind the tail lights so we're going to remove some interior panels. The first up, we'll go ahead and open up the hatch. Then we'll take the spare tire cover and fold it back. Now, in the inside edge, there will be two plastic fasteners that we have to remove. Then we'll go ahead and remove the threshold. A steady pressure pulling up on the bottom edge pulling straight up will get to release in the clips.

Maybe it will be helpful to pry in from the outside edge as well. Now, before we can move our anterior panels, we also need to remove the film inserts that are around the spare time. We'll put this aside. Then next, we need to go ahead and remove the interior cover. Take it up and put it out of the way for now as well. Then we'll loosen up the interior panels in the side.

At the bottom of our threshold, we need to remove a plastic fastener there. We also need to remove the tie-down point as well on the inside edge. We also need to remove interior cover on the inside edge right behind tail lights. Then we'll gently pull back the interior panels just enough to get our hands behind it Next thing, go ahead and start working with the wire harness. We'll take the wiring harness ends with the yellow wire and the red wire.

We'll go ahead and run it up behind the anterior panel and out the opening. Then we'll go ahead and just connect the wiring harness that goes right into the taillight with the matching ends. There's a small tag where to push down then pull it apart. We'll take the new Curt T-connector and go ahead and push it into the existing taillight socket and the other half will go to the factory wiring harness on the vehicle. We'll do two places on the driver's side.

Connectors are in two different shapes so you can't get them wrong. Now, we have some white wire from the ring terminal shown here. We're going to take that and peel that back down towards the bottom so we can attach it to some sheet metal down below the threshold. Now we're going to use the self-tapping screw that comes with the kit and run through the sheet metal below the threshold. It's a good idea to go through two pieces of sheet metal that are overlapping to give you more material to dig into. Now, we'll go ahead and take our key connector with the green wire and we'll go ahead and run it over to the other side. We're going to install just like we did on the driver's side. Now all the wire connections are made, we'll go ahead and secure our converter box. We'll clean it up the converter box and we'll also clean off the section of plastic on the inside of your panel. Then we'll use an adhesive to help hold it in place. Take the adhesive and attach it to your converter. Go take your converter and attach it to the inside of the panel. Then we'll use the zip ties that comes with the kit and go ahead and zip tie our green wire to the factory wire harness going across. At this point, our wire harness is fully installed. We just need to go ahead and reinstall all the interior components. After our interior components are all reassembled, we'll go ahead and try the wire harness. We'll take our ground for a tester and connect it to the white wire. Then we'll test the brown wire for the running light circuit, then our yellow wire for a left turn signal and then green for a right turn signal. Now a break signal will be a constant signal on the yellow and green wires. Okay. It looks like everything is working. Now, we'll go ahead and show you how to use it. When you need to use it and run it out to your trailer, just go ahead and pull it out and shut the hatch on it. Just make sure you stay away from the latch on the center so it doesn't damage the wire. The seal around door will compress but won't hurt the wire when you shut it. We'll also put on our cap for our four-pole as well. When we don't need it, we'll go and store the wire harness with the spare tire. Now, we're finished for the install of part number C56011 from Curt on our 2013 Mazda CX-5. .

Greg N.


Can a 5 or 7 pin plug be connected to the C56011 kit?

Les D.


@GregN the Curt # C56011 wiring harness creates a flat 4-way connector on your vehicle. You can add the #ETBC7 to upgrade your 4-way to a 7-way connection. Regarding a 5-way, would this be for a flat tow situation, or maybe a boat with electric brakes?

Tony B.


The wiring harness installation on my Mazda CX-5 went on flawlessly, thanks to your video! Thank you

Patrick B.


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