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Roadmaster Tow Bar Wiring Kit Installation - 2021 Jeep Grand Cherokee

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How to Install the Roadmaster Tow Bar Wiring Kit on a 2021 Jeep Grand Cherokee


Hey everybody, Ryan here at etrailer. Today on our 2021 Jeep Grand Cherokee, we're gonna be showing you how to install the Roadmaster diode wiring kit. But before we do that, why don't we check it out, and make sure that this is something that's gonna work for you. I figured it'd be useful to kind of cover the five main components that we're gonna need to flat tow our Jeep down the road in the first place. That way we can kinda just refresh ourselves. So the first one's going to be the base plate, and that's going to provide us with a solid and reliable attachment point.

That way we can hook our tow bar up to it. And that tow bar is gonna be the second component. All right, and that's gonna be the physical link that connects the front of your Jeep to the back of your RV. Third main component will be safety cables, and those are pretty straightforward. You know, they're in the event of an unlikely disconnect.

They're gonna keep your motor home connected to the Jeep. The fourth main component is going to be tow bar wiring. And what that wiring is gonna do is transfer the lighting signals from the back of your coach to the back of your Grand Cherokee, keeping you safe and legal. And last but not least, the fifth main component will be a braking system. And what that's gonna do is apply the brakes in your Jeep whenever you hit the brakes in your motor home, helping to bring you to a more complete and predictable stop.

So the way the wiring is going to work is whenever you turn on one of your lighting signals in your motor home, it's gonna be transferred here to the back of our Jeep. So when you have your left turn on, your right turn, your brakes, or your tail lights, people are gonna be able to see and know what's going on whenever they're driving behind you. And that's gonna keep you not only safe, but legal as well. So when it comes to tow bar wiring, I always recommend the diodes. And I say that because, main reason, they're super easy to use.

So there's really no setup time involved. Once you have them installed, all you're gonna have to do is plug in the front of your Jeep to the back of your motor home. And they look really clean too. You know, you're not even going to notice that they're there, it looks completely factory, so that's definitely a bonus. Compared to some of the other wiring kits that you could use, like magnetic lighting for example, in my opinion, the diodes have a major advantage. And that's because, one, the setup time, and two, you don't have anything to store. You know, with magnetic lighting, you're gonna have to set them up every single time you wanna use them, and not to mention whenever you're done using them, you're gonna have to take everything apart, and more or less find a good spot to store all this wiring and lights. And as we all know, whenever you're over the road and your motor home storage is very limited, so why use anything that will take up that extra space when it doesn't really need to So I talked about how easy it was to set up, and all you're gonna have to do is take your cable and plug it in to the front of your Jeep here and into the back of your motor home. Now there's several different kits available. So let's go ahead and kind of cover and figure out which one will be the best choice for your particular situation. The three most common ones we have here are gonna be the six way round end to the seven way. And it's really just gonna depend on what type of tow bar you have, which kit that you're gonna need. This one here, six way round to seven way, and it's a coil-type cable. And you would use this particular setup if your tow bar does not have channels in it. All right, and that's because with the coil-type cable, it'll stay nice and tight, high off the ground whenever you're going straight, but it's gonna extend and give you that extra length that you need whenever you're going around those turns and things like that. If your tow bar does have channels, there's gonna be two other kits available. One's gonna be a hybrid type cable, okay, so the straight portion can run through the channels in the tow bar. And at this end, there's gonna be some coil action going on here. And this would be a kit that you would use, particularly if you have a really long tow bar, if you have a lot of distance in between the front of your Jeep and the back of your motor home, this is gonna give you a little bit of extra length. The other one is just gonna be a straight cable. A six way round and seven way, and again, you're gonna use this if your tow bar has channels that we can run the cable through the channels and everything will be set up properly. There's two other kits I have right here, and these aren't as common, but are available. One of them is gonna be a coil-type table with a four way round connector, this side would plug into your Jeep. And seven way on the other end. So pretty straightforward, does the same thing as the other coiled cable that I mentioned a moment ago. And then there's also going to be a four way flat. So if your set up needs something like this, you know, this is always an option. And as I mentioned, the seven to six are definitely the most common, and that's what we see here the most. And there's also one other kit available, and it's a kit that does not come included with a cable at all. And that's there for those of you that have a premium type tow bar. A lot of those premium ones actually come included with a cable and a plug. And so that would be the kit that you'd wanna use if that is your tow bar setup, if that's the type of tow bar you have. 'Cause with those components being included, it don't make sense to get a kit that has extras because you're gonna need two of them. So at the end of the day, in wiring kit, you really can't go wrong with. We've had a ton of luck with them, and they're super easy to use, so you really can't ask too much more from a kit like this. With that side, as far as the installation goes, it's not too bad, nothing really super complicated, but it does take a little bit of time, particularly routing the wiring. We get a lot of questions about that, but I'll show you how I did mine, and you should have some pretty good luck with it, really shouldn't give you a whole lot of issues. Speaking of which, let's go ahead and hook it up together now. To begin our installation, we're gonna be here at the front of our Jeep. We clearly that they have the front facia removed, and that's because we're doing this at the same time that we're doing our base plate, makes it a lot easier. With that said, you don't have to do it that way, it is possible to do it with the facia on. It's a lot more time consuming. With that said, what we're gonna do is take one end of the bundle of wire and just place it by where we're gonna mount our connector up, which is right here. Gonna take the rubber boot, put that over the wire, get that out of the way for now. And then we're just going to separate the wires from each other. So carefully take a pair of snips, cut in between, and we can peel these back a few inches. What I like to do is just cut a little bit off the ends there. Kind of give us a fresh start of wire. And then we're gonna strip back the insulation on each individual wire to expose that bare wire underneath. So once that is done, you wanna give these a good twist. And that will not only make it a little easier to plug into our connector plug, but also help out with the connection as well. Give us a little more of a solid connection. That said, we can grab our connector plug. And the way these are gonna work is we're gonna have set screws. And you want to loosen up the set screws pretty much all the way, but you don't wanna pull a screw out 'cause if it falls out, it's hard to find, little tricky to get back in. But we're gonna be using four of these terminals, and they are labeled. This one here is TM for taillights, so that will be our brown wire. GD is ground, so that will be our white wire. LT, which is this one here, that'll be left turn, so our yellow wire. And this one here is labeled RT for right turn, so that'll be our green wire. So what we'll do is take the appropriate wire and put it in the corresponding terminal. So we'll start with our taillight signal. So that'll be the brown wire. We'll put that in, simply tighten down the set screw. Let's get that tight, we'll just do the same thing for our remaining wires. Here's what the connector looks like once all of our wires are hooked up. And once that is done, take the rubber boot, place that over. At the very end, once we verify everything is working and we're done with our flat tow setup, what I like to do is come back and put some dielectric grease and seal everything up really nice in here, help prevent any corrosion, and things like that. But I like to wait to the end to the end, that way if there's an issue, or we need to look something else up, we're not dealing with that big mess in there. With that said, gonna take some screws here and get this secured. And then you're going to want to start to route your wire that comes off the back of it. So I just ran it behind your bumper here. So here's where our wire comes up into the engine compartment. And I simply just continued to route it this way through this panel here, there's some factory openings, where it comes out there, and then way down at the bottom, there's a factory grommet. You can poke a hole through that and route your wiring through it to the underside of our vehicle. So now underneath of our vehicle, here's where our wiring drops down, and let's have it drop down, secured it to this brace. And then once you get to about this point, what I'm gonna do is separate the white wire from the rest of our harness. So we're gonna take a pair of snips, and very carefully cut just that white wire. All right, and then what we're gonna do with it, so this is the side of the white wire that goes to our connector plug there at the front of our vehicle. Gonna strip the insulation back. Gonna take the included ring terminal put that over the bare end of the wire and crimp it down. And what we're gonna do with this is ground it. So we wanna go on a clean piece of metal anywhere right here will work, honestly. We'll kinda see which way is the easiest to get our drill in which looks like it'll probably be this area, but we're gonna take the self-tapping screw, pick out your spot, and get it secured. So with that nice and tight, what we're gonna do is take the other end of that white wire, and we simply just want to completely remove it from the rest of our harness. When we do that, you wanna hold on to that extra wiring because we are gonna be using it here in a little while. And once I have this completely removed from the rest of our harness, I'll continue to route our harness here towards the back of our vehicle. So I continue to route that wire. And when you're doing this, you wanna do your best to avoid any hot or moving parts. So I just ran it along through here, using some zip ties along the way to keep everything secure. So this continues straight on back, where it's going to be ran on top of our subframe, up through here, continues along where it will eventually come out right there. And zip tied it up through here. And at this point, what I did was separate our green wire from the yellow and brown, also took that extra piece of white wire and started to route that. So all I did our yellow and brown wire, took the end of the white wire and taped it to the end of the yellow and brown wire. So that's this bundle here, we're just gonna let this kinda hang for now. The other end of the white wire, I just taped to the end of our green wire, and I routed this over towards the passenger side, just runs along through there and drops down right here. So now up here at the back of our Jeep, need to get the lights out. So you open up the hatch, that'll expose two push pen-type fasteners. So take a trim tool, or even a flathead screwdriver, going to pry out the center of the fastener, and then get behind the base of it, and get that removed. Do the same thing for this one here, set them down, and then we can grab our light. And what you're gonna do is just kinda work it. Help kinda loosen it up. Sometimes these gonna be pretty tight in here. And I just kinda pried down on the top and pulled back. And now we need to disconnect everything. So it'd be easier to pull up on that red tab and push down on the center. And all three connectors are going to work the same way. So once I have this removed, I'll set this to the side and do the same thing over on the passenger side. Just removed some of this tape that was there on the factory, off these wires, that way we could work with them and get them tested. So I went ahead and tested them, and what I found was this one here, it's got the little bit, you know, smaller plug on it, the white wire with the light gray stripe, that's going to be our taillight signal, and this larger plug here, it's gonna have a solid white wire on it, that's going to be used for our stop and turn signals. So what we need to do is we're gonna cut these in half, and we're gonna just strip the back the ends of the insulation. And we'll give them a good twist. Be careful when you're doing this, these wires are pretty thin. So just take your time, pay attention to what you're cutting. Get this one finished up. And what we're gonna be doing with these is each end of the bare wire is going receive a blue spade terminal here. So get this set up, place the wire into the terminal, and crimp it down. I'll do that same thing for our three remaining ends. Now what I've done is taken a pull wire, I'm just using a piece of tubing, but you can use a coat hanger or heavy piece of wire, kinda whatever you have laying around the house to do this, drop it down through our taillight pocket, to where it comes out the bottom side of our vehicle. And I simply just taped our wiring to it, that way you can start to pull our wiring up into position, and then I'm gonna trim it to length. You know, I like to keep a little bit of extra wire here to work with, so we'll cut it about there. And then we're gonna strip back the ends here. And we're gonna crimp on some terminals, just like we did a moment ago, the only difference being the white wire and the brown wire, what you're actually gonna do is twist these together. Twist the two bare ends together, try to get these nice and tight. And on this one, you're gonna place the yellow spade terminal over both ends of the wire. And we'll get this crimped. With that done, we can get our blue terminal on the yellow wire here. Now we can start to plug in our diode. So this wire here, the big plug with the solid white wire, that's what we're gonna use for our stop and turn. So you're gonna take your diode, the single terminal that says out, place that there, you want that closest to the plug. Get these untangled here, and we're just gonna go color for color. So the other side of that solid white wire will get plugged in there. And since he's our stop and turn, we're gonna take our new yellow wire, plug that into that diode. Pretty much the same deal with this setup here. I'll go to the end with the connector plug, color for color. And since the white wire with the gray stripe's gonna be our taillight signal, we're gonna take our yellow terminal there that has the white and brown wire that we ran and plug it into this diode. With our diodes all hooked up, you can simply plug your taillight back in and kinda feed all the wires down. And this area here is really tight, so what I'm gonna do is try to hold our diodes in place here, along this connector, and see if we can't get our light back in. Not a ton of space, so this might take you a couple of tries, and just be careful lining and everything back up. You know, once you get it in, it's gonna be nice and snug. So the diodes aren't gonna go anywhere, but at the same time, make sure you're not gonna pinch any wires or really force that light back in. If you find that sweet spot, it will kinda more easily go back into place. Over here on the passenger side, I've essentially hooked everything up the same exact way with one exception, and that's just the colors of the wires. So this one here, the big plug, the white wire with the green stripe, that's going be our stopping and turn signal. So our new green wire that we ran we'll plug into that diode. The smaller connector here with the white wire with the orange stripe, that's gonna be our taillight signal. And so the solid white wire that we ran we'll get plugged into that diode. But all this hooked up, we'll go ahead and get our light back in, and then check everything to make sure that it's working properly. Can test our wiring, now. So I hooked up to a test box, turned on our taillights, our left turn signal, our right turn signal, and our brake lights. And that'll finish up our look at and our installation of the Roadmaster diode wiring kit on our 2021 Jeep Grand Cherokee..


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