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Demco 5th Wheel/Gooseneck Wiring Harness Installation - 2021 Ram 2500

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How to Install the Demco 5th Wheel/Gooseneck Wiring Harness on a 2021 Ram 2500


Hey, everybody Clayton here at etrailer.com Here at etrailer.com we install, test and review, a lot of different products. To help you as the customer, make a more educated decision before your purchase. Today we're going to be working on a 2021 Ram 2,500. We're going to be taking a look at, and I'll be showing you how to install the Demco in bed 5th Wheel/Gooseneck Wiring. Adding a seven way to the bed of your truck, for when you're using a gooseneck or 5th wheel trailer is going to be essential. We're going to get all the same lighting functions in the bed of our truck, and we're not going to have to have that wire dangling out of the back.

There's more oftentimes than not that wire drags ground or gets pinched in the tailgate and ends up damaging your wiring. So this is not only to make life easier but it's also going to help save your power cord. I know all the guys out there are worried about the in bed wire and working with the ram boxes but as you can see, our truck here has the ram boxes and our in bed wiring works just fine. Now, keep in mind that there's a little bit of difference but it's definitely doable. This is what our seven-way is going to look like installed.

As you can see, this is our plug right here, with a nice lid. This is constructed of a high durability ABS plastic. It does have a spring here in the top of our lid. So we don't have to worry about that getting opened or any dirt or debris getting inside. And it does open 180 degrees.

So it is going to be easy to get that plug in and out. And one nice feature is there is a catch here for your wiring. So once that's plugged in, it'll stay nice and tight to the plug. Another nice feature that I like is there is some gasketing on the inside of this plastic here to catch this lip. That way it stays nice and sealed.

All the lighting functions, we're going to get back here at our seven way, they're going to be the same as the seven way that came with our truck. Now this is going to be our left turn our right turn, our brake, our taillights, our charge line or our tool bowl as is it's usually called, our reverse and our brake line circuit. This kit is going to include everything you're going to need to get it installed. One feature that I like is it is plugged in place. You're not gonna have to do any splicing with any wiring. So that makes life pretty easy. The only thing you're going to have to do is drill a hole in your bedside and run some self-tappers in to secure your plug. Our kit is going to have copper covered wires which are going to be super weather resistant. So that's going to hold up really well for a long time. And not only that, all of our wires do have wires pre-installed so you don't have to worry about wires getting cut on any rough edges or anything like that. And our power or our cable between our in bed plug and a plug that plugs in down below, is about 10 feet long. So that's going to be really nice, cause if you want to put this in the front of your bed, you definitely can. Now, since we do have ram boxes this is the only place we could do it. But if your truck does not have ram boxes, you can pretty much mount this anywhere, but the ground. And in terms of installation, getting this installed really isn't too bad. With that being said, I'll go ahead and walk you through the installation portion now. To start our installation, we want to make sure that our plug is not going to come into contact with our ram box. So if we just open that up and look on the inside of the ram box, we want to line that up in our bed to where the back of our plug is not going to make contact with this plastic lining or any of the wiring for the lights in the ram box. We're going to have to move this plug almost all the way back on this lip. So we just want to take it like this, kind of hold it up against there, kind of make a mental note of where the center is. We just want to flip that over and do the same thing. I went ahead and just put a center marker right here. There actually is a little dimple. So that's going to make drilling it a whole lot easier. Now with that marked we can grab a small drill bit and draw out a pilot hole. We have our pilot hole drilled. We can move up to our hole saw. I just want to take our two inch hole saw, and drill this out. Behind our hole, there is actually a channel that's going to run from here to the outside of our truck. So we're going to want to grab a pry bar, just kind of reach in here in pry this out a little bit. That way we can get another tool in there to help cut this out. So now you can kind of see what I was talking about. There's this kind of plating behind here, now we just need to grab an air saw, or even like a jigsaw anything that you can really grab in here, or like a saw saw with a thin blade, just to reach back there and kind of cut that bracketing off. This is what it's gonna look like inside there. We just kind of cut those edges out and knocked them back to where we can get our plug in there and turn it 360 degrees. There's a little bit of play. Now I just want to come back with some clear coat and spray that over all of our fresh cuts, just to protect it from rust. We just want to grab our wiring and drop that down through our hole. And this might be kind of tough if you're having trouble doing this, you can always pull that wiring up from the top. You can just drop our wiring down. You wanna make sure it doesn't get caught on that wire on the inside. I just want to grab some dielectric grease and apply that to all of our pins. You just want to do this to ensure a good connection. You can find dielectric grease here at etrailer.com. We can just grab our seven way we'll line that tab up with the tab on our plug. Kind of push those together, and hear that nice click, and straighten our wiring out and then push it back into the bedside. Now I just want to grab our seven way plug make sure that it's nice and straight. That looks pretty good there. We can grab our provided self-tappers, and get this screw to the bedside. Just like that. We'll repeat that same process for our remaining hardware. With our seven way plug installed. We can now move underneath and plug in our wiring. This is where our wiring dropped down. Our model does have this step here but I'm going to go ahead and run it over to our plug and then show you the route we took. So this is where our harness drops down, right up and over our frame rail, and up and over our spare tire. I actually loosened our spare tire to help you see it. That wire just runs up and over our spare tire assembly and out to the other side. Before we go any further, we are going to add dielectric grease to our pens down here. You do want to add a good amount. Right here's going to be our factory connector, there's going to be a little tab right here that we're going to push down on, and push down there, now wiggle our plug, and then pull it out. Now we can grab our new wiring, we're going to plug the larger end into our factory connector, lining up those tabs and push down. Till you hear it click, give it a nice pull, make sure it's nice and secure. Then we'll take our new plug, I want to make sure that our tab is in the same orientation. Align that up, flush down until it clicks. We know it's nice and secure. Now we can zip tie our extra wiring up and out of the way. With all of our wiring tidied up. We can now reinstall our spare tire. Now we're going to jump into the cab of our truck and get everything tested with our test box. We're going to start off with our brake signal, our left turn, our right turn and our taillight signal. Now we have our tester plugged into our original plug just to make sure everything works. Start it off again with our brake signal, we can do our left turn, our right turn and our taillights signal. And when you're testing it out at home you can just plug it into your trailer and test all the same functions to make sure your new plug and your old plug for both working properly. Now, with that being said, we have everything installed and ready to hook up to our gooseneck and hit the road. That's going to do it for our look at any installation of Demco 5th Wheel Gooseneck Wiring on our 2021 Ram 2,500..


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Employee Andrew K
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Employee Kathleen M
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Kathleen M
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Dustin K
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Employee Cole B
Installed by:
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Employee Shane H
Test Fit:
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Employee Clayton O
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Bradley B

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