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Roadmaster Universal Diode Wiring Kit Installation - 2018 Honda HR-V

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How to Install the Roadmaster Universal Diode Wiring Kit on a 2018 Honda HR-V


Hello, neighbors. It's Brad here at etrailer. And today, we're taking a look at the Roadmaster diode wiring kit for a 2018 Honda HRV. Now, this is going to be sending the signals from your motor coach to the taillights on your vehicle, and that way the people behind you know when you're signaling or braking. This is available in a few different options. You can get a six-pole, a four-pole, or you can also get it as just plain wiring, so you can add your own connection to it.

So as you can see, we have our flashers on. And as these flash, you can actually see the lights on the motor home as well flashing. So when I use my turn signals or brakes while driving my motor home, my flat towed vehicle is gonna mimic that perfectly. Now, the diode system takes the electricity and signal from the motor home and sends it to the taillight, and you splice into your taillight wiring. And the diode acts as a one-way, so that way electricity can't back-feed, and that's gonna keep not only your vehicle safe, but also your motor home.

So now, you can see all the connections that you have for flat towing. Obviously, you're attaching your tow bar to your arms here. You have your safety chains, which this will keep the vehicle attached to the tow bar and the motor coach in case of a separation. You have your electrical umbilical, which is gonna send your signals to the taillights and brake lights on your vehicle. Your breakaway switch is there in case this was to separate.

This will pull the cord here, and that's gonna put the braking system on the vehicle to bring it to a stop. So we actually use the bare wiring kit on this vehicle. And the reason being is our tow bar actually came with the umbilical as well as the connection to be made. Now, making this all work is pretty straightforward. It's a little bit of work 'cause you have to pull the taillights off, and you'll be doing a little bit of splicing, but I'm here to walk you through that.

So let's take a look at the installation. Now, as far as running your diode wiring, it's pretty straightforward. You're essentially gonna have to have your wire ran to the front as it's gonna connect to your connector that's gonna go to the RV. Now, from there, you're gonna have to route this back to the taillights to connect into those. Now, before you do that, if you are doing a braking system, I would highly suggest running a little extra cable here because you may need to tie into that. Now, if you're not putting a braking system in or if you have a system that doesn't require tapping in, then you can route that as necessary. But I did leave myself just a little bit extra, and you're gonna save a lot of headache trying to pull wires and splice into these. Now, the front fascia the vehicle is off and that's because we just installed our base plate. So if you're running your diodes and you've just done a base plate or are planning on doing it, this is a great time to knock it out at one go, and it's gonna make running the wires a lot easier. So from here, I used our base plate here as a good foundation. I left enough, we will be tying into our six-pin here. So you can leave a little bit extra as it's gonna help you out. So maybe tape this here and it'll hold it in place. And that way, when you're routing wires, it's not gonna pull back. But following the cable, we simply ran up. And that way, I could get to my battery. You can see I've gained my, I probably have a two foot or so, a little bit of extra wire here. And then from there, I routed it back down, out on this side. From here, I went under and the main goal when running wires is to stay away from anything hot like exhaust or any moving parts, whether it be an axle or drive shaft or suspension. So I'm gonna raise this up and show you the rest of the way that I routed it back. So I routed it down and I actually left our little splash shield here and simply tried to get this to a factory loom or wires, and that way I can run it back and know that they're gonna be safe from other elements. So routing it through the crossmember, that's gonna hold this in place. And I started zip tying here. Now, you have this undercarriage cover here, and to make it a little bit easier on yourself, you can remove there's some plastic pushpins as well as a 10-millimeter. And having this kinda out of the way is really gonna gain you access to run that wire safely back. So as you can see, I simply routed it here. And this is gonna make it easier to where you don't have to completely crawl under your vehicle. You should be able to do this from the side. And then, just following it back kinda brings me to the center here. So over this torsion bar here, I routed that up because this does move. That's part of the suspension. And then, I fed it into this back cover here. Now, these are pretty easy. You simply twist these little plastic nuts, and then there's also a Phillips screw over here. And that allows me to pry this a little bit. And then, I can route my wires to the back. Now, our white wire is going to be our ground, and you can really ground anything that's part of the chassis and it can kinda be wherever you need. Now, when we run the diodes, there is a jumper wire that goes from one to the other. So what I've done is actually gone pretty far back, and I'm gonna be using the extra length of wire that I cut after putting my ground on, and that's gonna be my jumper wire. So if you have extra wire at home, you're more than welcome to use that. We also sell extra wire here at etrailer. But if you don't have that and you're in the middle of the install, this is a good way to salvage that. So I'm gonna mount it just right here, so I'll go ahead and cut this off. And this is gonna give me plenty of extra wire to work with on those taillights. From here, we'll go ahead strip this. And included in the kit is a ring terminal and a self-tapping screw. So go ahead and get those handy. Now, what's nice too is this ground is gonna be protected by this cover, so it should hold up pretty well to elements long term. With all electrical connections, I try to give 'em a quick tug just to make sure that they're secure. Now, as far as putting your self-tapper on, sometimes putting the pilot hole makes it a little bit easier. But we should be able to get this pretty easy with this angle. Now, there is a flat spot on your ring terminal, and then you can see it's not as flush here. You want that flat side to actually sit against that metal. I'm also gonna try to find a spot that's not as painted as the paint can actually kind of cause the ground to not be the best. Now, if you're having trouble with the self-tapper going in, sometimes this metal is actually doubled up and it can be really tricky for these to go in. So finding a nice easy spot is gonna be beneficial. Just make sure on the other side, you're not gonna be poking through anything. And also with your self-tappers, you wanna tighten it down to where the ring terminal doesn't move. Like that. But don't go too tight as those threads can actually strip themselves out. So now, we have our ground in place, and we have our extra wire for the jumper. Now, leaving this open is gonna be nice because we are gonna have to tie into both of them with a jumper wire. So from here, we're gonna lower the vehicle down, we'll get our taillights out, and see what we're working with. So we'll be tying into our factory taillight harness, and that's gonna give us those signals for our brake lights, our running lights, as well as our turn signal. So we're gonna have to pop these off. Pretty easy, you have the two eight-millimeter screws here. Just go ahead and remove those. Now, once those two are out, it comes out fairly easy. There is like a pin that it kinda pops into, so you may need to give it a little bit of wiggle, maybe a quick little bump, but it should come out pretty easy. And that's gonna gain us access to our factory wiring here. Now, I went ahead and I've tested the lights here. So I know which cables are actually going to give us our brake light and running light. So you're gonna want to make sure that's correct. I just used a light probe and had someone press the pedal and turn the lights on. So I know which ones are correct, but we're gonna have to gain access to these wires. And as you can see, this is kinda tucked down and it's not gonna allow us for a whole lot of room. And also, there's this wire loom on here. We also have our diodes that we're gonna have to hide somewhere. And they're, as you can tell, not exactly small. And there's two of 'em. So planning accordingly is gonna help you out here. Ideally, we'd like to kinda place some down in here, so we're gonna need to account for that when doing our wiring. But we're also going to need to fish up our wires that we ran back. So in order to do that, I actually have some spare air line tube and you can use a string or a hanger or whatever you may have to pretty much pull your wires up. It's gonna make it a lot easier. So you can just feed these down, and then go on the bottom side of the vehicle. And that way, it's poking out both sides, and then we can tape our wires up and pull these up. So from the factory, they have tape wrapped around this wire loom, and we're gonna have to gain access to these wires to tie into 'em. So peeling this tape off and getting that wire loom out of the way is gonna allow us a little bit more room when splicing into our wires here. And if sometimes that tape is tricky, you can't just peel it off like that, you can use a utility knife. Just be very, very careful not to splice. So kinda cut away from it, obviously. Once we have a little splice, we should be able to peel this back a little more. And also from the factory, these are kind of looped into this little spot here that simply just pops out. And I think that's definitely something you're gonna wanna do just to make it a little bit easier to get to these wires. So I'm gonna go ahead and I'm gonna peel this all the way back, and that's gonna give us access to a decent amount of real estate here. So this should be enough for us to gain access here pretty easily. And I'm kind of thinking that this will work out well because our diodes, I wanna tuck 'em down in here. These actually sit down, so if we can tie into these, that should be pretty easy. So you do wanna test these with a light probe. Our white wire is our brake light, and then our running light is gonna be our green. So these are gonna be the wires that we're gonna need to actually get to. So before we do that, we're gonna need to pull up our wires from underneath the vehicle. Now, it is important, the colors, so I'm gonna show you which ones you need to do. So now on our driver side, we have our yellow, which is gonna be for our left turn; our brown, which is gonna be for our brake light; and then, we have our extra wire that we used and this is gonna be our jumper that's gonna go to the other taillight. So I'm gonna feed this up using my pull wire. I'm just gonna tape this on. Try to get the ends of the wire, and that way it doesn't have anything to really catch on as you pull it up. It's kind of a tight spot, so having a little smoother end here is gonna make that a little bit easier. Now, we can pull our wires through. And again, if they get hung up, just kinda take your time. You may need to go to the bottom and kinda make sure that it's not catching on anything. But you really don't wanna pull too hard. Sometimes, kinda just bouncing that whole wire around can loosen it. But it seems like we're caught on something, so I'll go under here and kinda just see if we can't help these wires out a little bit. So now, with our wires pulled through, we'll take our pull wire off and we're gonna go ahead and get these spliced as we're gonna need to connect to the diodes. Now that we have our wires pulled up, we're gonna need to make the connection here. So again, earlier, I said we're gonna try to hide those diodes down there, so I'm gonna try to make my splice here. And that way, I have enough to work with on both ends, but also I can put these diodes down. Go ahead and make the cut on the green and white wires. Then, we'll splice both ends. So we'll go ahead and take our little spade connectors here and attach these. Now, the other side, we have our spade connectors as well. So now, we're able to put our diodes in place. So we are essentially jumping in between these, and so you're gonna see there's an in and an out. So the out is actually gonna go to the taillight, so we can go ahead and plug these to this side that actually goes towards the bulb. And so now, you'll see that we have these two. Now, we're also gonna need to tie in our other wires here, so we'll go ahead and get our spade connectors on these. So our yellow wire is our turn signal. So our white wire, being our brake light and it will be our turn signal while in a towed mode, this yellow will need to attach to that. Now, on the diodes, you're gonna also see with the spade connectors, they're mostly blue. There is one yellow, and that's where this one's gonna come into play here because we're gonna be tying into two wires into one diode. So the way we're gonna do that is we are actually going to attach our jumper wire as well as our running light here. And this jumper wire is just gonna feed that same connection to the other side of the vehicle. And this spade connector is larger for the two wires, so it's gonna make it a little bit easier for you. Now, we have our green one here. You can go ahead and attach our yellow spade connector. So this is going to be your running lights. So now, we'll just finish up the connection here. So we'll put our green on here and that may get a little bound up here, so just gonna be patient as this spade connector is a little bit larger on the yellow. And now, our other connection here on our white. That's gonna hop in, get it plugged in right here. So now, we have a little bit of extra wire. We can pull some of this slack down or just push it down and we're gonna try to get these diodes kinda tucked in there. Now, a little helpful hint, a little black silicone here placed in is gonna help kinda make sure that these connections stay good. No condensation or corrosion will build up. So I'm gonna go ahead before putting this in and put a little black silicone in there. So I've routed up our running light as well as our brake and turn signal here. And we've spliced in just like we did on the other side, so you can see our white wire went to our green wire, which is gonna be again, our turn signal there. And then, the green wire actually gets our jumper wire, so ours is white in this instance. So whatever jumper wire that you have running from the other one, that will attach to our green. Now, to give yourself a little extra room, you can unclip this portion that's on the taillight and that can help slide this down, but I do believe it should fit. There's also double-sided tape. So if you want, you're able to stick these together and maybe throw a zip tie to kinda keep 'em bundled. But I do believe we should be okay to be able to fit these in. So I'm gonna go ahead and put silicone in all my connections here, and get our taillights back up. So now, all that's left to do since our taillights are all hooked up is make our connection at the front. Now, yours may come with a four-pole onto it, and if you're hooking up to a trailer and not using brakes, then that's great. If you are planning on using brakes though, you're gonna need to use a six or seven. So our kit actually came with the six, so we'll be wiring it up to this. And if you don't have a connection, you're gonna need one in order to attach to what you're towing with. So we have those options here at etrailer, and you can choose the one that's best for your application. So when running your connection, generally, you'll have a boot here if you're doing a six or seven. You're gonna put that on first, and that way you can make your connections and this will create a seal onto it. So with our fascia now reinstalled, really all we have left is to make sure we have our wiring hooked up. And you're gonna see these two little pegs here have threaded ends, and that's gonna put our plug in place here. So let's get this connected. So marked on our plug itself, you're gonna see little letters and that's gonna correspond to where these go. So let's start it off with our green. Now, this is gonna be your right turn signal. So you're gonna be looking for RT. So if you have a small Phillips screwdriver, back that screw out. And then, once you feed that in, you can go ahead and tighten that down. Next, we'll do our left turn signal, which is gonna be our yellow. And next to our right turn, you're gonna see the LT, so we're gonna put it in there. So I have all my wires in place. So just a quick check, we're gonna have our green going to the RT, which is our right turn signal. Yellow is gonna go to LT for left turn signal. Our white is gonna go to the ground, which is GD. And then over here, you have TM and that's your trailer marker or your brake light and running lights. So make sure you have all those corresponded in the proper location and tightened down. I'm covering my contacts here with a little bit of dielectric grease, and that's just gonna kinda help prevent any corrosion from getting in there and it's gonna keep our contacts nice and clean. Now, we'll put our little boot here, just slide that over. And just to give it a little added protection to make sure water or corrosion doesn't get in here, I'm gonna actually take some electrical tape and wrap this up. And that way, it's gonna be nice and sealed up for us. So now, we have this nice and wrapped up. And what's left to do is mount this on here with your self-tappers included in the kit, and just go ahead and hook this up. Now, we're good. So now, you're gonna wanna test your wiring and the way to do that, you're gonna wanna hook up to your RV. You might have someone stand by inside the RV and run through the sequence. And that way, you can see it on the back of the vehicle working. We have a test box here, so we're gonna run ours through the sequence. So first, we'll start with our taillights. Next, we're gonna go to our left turn signal, our right turn signal, and then finally our brake lights. With our wiring working properly, all that's left to do is hook up the rest of our flat tow components and hit the road. And that was a look at the Roadmaster diode wiring kit for the 2018 Honda HRV..


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