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Roadmaster Variable Voltage LED Tail Lights Wiring Kit Installation - 2021 Jeep Cherokee

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How to Install the Roadmaster Variable Voltage LED Tail Lights Wiring Kit on a 2021 Jeep Cherokee


Hi there Jeep owners, Standard 2021 Jeep Cherokee, we're gonna be taking a look at and showing you how to install Roadmaster Smart Diode wiring kit for models that have LED lights. Our Smart Diode Wiring kit is gonna take the lighting signals from our motor home and transfer them here to the back of our vehicle so that the people behind us will know our intentions when we're flat towing our vehicle down the road. You can see that the hazard lights I've got them turned on in our motor home and as it flashes there, it also flashes here in the back and mimics the signal. Now it is gonna be a little bit different than your natural lighting when you're driving the vehicle around. The Jeep here, if it has the park sense, which we do have park sense on this Jeep here. It's required to have the smart diode kit instead of a regular diode kit.

With a regular diode kit, we can actually make the lights function very similarly to how they we're when you're driving the vehicle. But due to the park sense, it is special and pretty much the only way to get the lights to work here on this particular Jeep. So it uses the taillight circuit and it varies the voltage to that taillight circuit to give us all of those necessary lighting signals. We've got the brake light lighting up here where it's flashing, it's the same as the turn signal and that's the full intensity. If we turn on our taillights, this would change to a lower intensity, which would be similar to how it would be just on your vehicle.

Your taillights are gonna be lower when you hit the brakes, hit brights, it lights up brighter. Sometimes it's the same bulb, sometimes it's a different bulb. On our Jeep when you're driving it around normally, your brake light would be the center one here, but our smart dials give us the exact same functionality using the tail light that's right here. Because the main thing here is that we're getting all those signals here at the back of the vehicle, so everybody around us knows what's going on. Trying to keep ourselves safe and everybody around us safe by keeping everybody aware.

And I went ahead and turned the tail lights on here so you can see the difference between the bright and dim, going from tail light to full brake or turn signal light, and you can see the difference here between no light over here on this section versus the it's a little harder to see here during the day, but you can tell the difference between this is being lit up and this one not lit up at all. Diode wiring is my personal favorite style of modification to get our lighting signals here at the back of our vehicle. The reason why I liked the diode wiring is because it's a permanently installed component here that's hidden inside the vehicle, you don't even really know that it's there, there's kind of nothing that really tells you is there except for the connector that's at the front of our vehicle here broken up to our flat tow setup. And it makes it nice and easy 'cause to make our diodes work here after you installed them, you simply just plug your same way connector into your motor home and plug the other end into your vehicle here and they're up and running right after that. With other styles like your magnetic lighting, you have to get those out every time you want to flat tow.

So unlike this will just plug it in, I'm ready to roll, I got to get the box up, it's got my magnetic lights so I got to set it up on the roof, and then I gotta run the wire up to the front and it's not gonna look pretty when you're doing this the whole time, you're gonna have wires running across the top, there's pads on the bottom of the magnetic lights to prevent scratches and abrasions, but over time, those pads can wear out and you can get some abrasions up there on the roof. So with this you can avoid all that mess, it is a bit more of an install upfront to get those on, your main headlights they just set up there. This one, we are gonna stick a few components apart and write a little bit of wiring, but if you follow up with me here in the shop, I'll show you how to get it done, it's not nearly as intimidating as it may seem. And with the smart diodes, it really does kind of, everything's kind of nice and laid out for you to get that done. We'll begin our installation here at the back of the vehicle with the lift gate open. Now that's gonna reveal the two fasteners that's holding our taillight assembly in. We'll be removing these on each side, we'll take our T30 Torx socket. And we're gonna zip these out of here. Now with our fasteners removed, we'll take the assembly and you kind of wanna just rock it back and forth, kind of up and down, and there we go, it'll pop it right out of there. We flip it over, those are the two prongs that we're holding it in there so that's kind of what we we're wiggling to get that out. After you get it out, the lock tab here is probably gonna be endless with this one's already popped open. To open it, you simply just push it out, this is what it would look like. We can then press in on the release tab here and separate the two pieces. Now that we've got that one removed, we'll take the wiring here and we're gonna take a razor knife and we're just gonna slice down our wiring here to get this removed. You do wanna be careful when doing this, we don't wanna cut our wires. So we're just gonna really carefully get this removed. This can take a little bit of time because you do wanna go slow. After I cut a little bit, I'll peel back some of it to make sure that I'm not nicking any wires. And I'm gonna keep on slicing down until we get it, till about this point here. So now that we've got that all cut back, it gives us access to the circuits we need. We want our taillight circuit, which is gonna be pinned three on the connector. If you look at the corners, there are numbers there, one, the middle ones, there's no number for two, but then when it gets to their corner, it's labeled three there so you can easily find that. On the driver's side here, it's gonna be yellow with a white stripe also for the color for that pin three. So now that we've got that identified, we can go ahead and cut this wire. So we're just gonna cut it at about this point, give ourselves plenty of excess there to work with. We'll then strip back each end of the wire after we cut it. And it might seem a little strange that we're cutting the taillight circuit, 'cause when you look at your smart diode, it tells you to hook it into the stoplight circuit. But due to this vehicle having park sense, we're gonna get around the computer module and get our proper lighting using the taillight circuit and everything should work out just fine doing that. So we're just twisting those to make it a little bit easier to slide our terminals on. Here's our diode, already removed the ground one, that's just gonna hook to a small piece of wire that comes in your kit. So we're concerned with the ones labeled car because we cut the wires on our car here. So car out here. I know it says break and we're gonna have the tail light and car break in, we'll do this side here. Out it's always gonna be the side that goes to the lights. So we're just gonna pull off both of those and then grab our crimpers. We're gonna crimp one of these onto each of the wires that we had just cut. Slide that in there, crimping it down, and we'll do the other one, and we're gonna do the same thing with the other end of that wire. And now that we've got those cuts, we can take our smart diode here. We can go ahead and plug it in, so connector side, we're gonna plug into the car out. Car in goes over here to the other side of our wire, and the ground. We pulled that one off already and we attached it to the small white wire that comes in our kit, just crimps on there. So we can go ahead and slide this on here, back onto the ground. And on the other end of our white wire here, we're going to crimp on a ring terminal, you'll get some ring terminals in your kit, as well as some self tapping screws. Just grab those here. You'll use one of these small ring terminals and one of those self tapping screws. So we're gonna save ourselves tapping screw for a moment. Slide our white wire down through the ring terminal. Go ahead and crimp this down. And then we're gonna take the self-tapping screw, comes in our kit, we're gonna slide it through the ring terminal, and I'm just kind of running it over here and we're gonna run it right down into the metal here. So I'm gonna grab our gun with an eight millimeter socket on it, and just about right there is fine, just to run this right in. Unless you can get it down, we want it to be solid, so it's a little bit, I still got some rotation on it. I do try to put it towards this side, just 'cause it'll angle down. And then we just want to make sure it's snug to where we can't rotate it, so that's nice and solid there. Be careful not to over-tighten this. The metal's not super thick here, so you definitely can't over-tighten this to the point where it's gonna be loose and it's not gonna give you a good ground. If that's the case, you can just move it up or down a little bit and run it into a new spot. You can fill in your hole down with some strong black silicone to seal that up. You can get that here at Etrailer if you do need some. Next, we need to get the wiring that comes in our kit, you'll get this big long four pole wiring, you got four wires there. It needs to go from down below, up behind our cavity here to connect to our diodes. To get it here, since it's a pretty tight opening here, we're gonna use a fish wire. Now I'm using some airline tubing, but if you we're doing this at home, a metal coat hanger works really well. You can kind of get that straightened out so you can poke it down through there, it's got enough flex in it to kind of get around some things, but it's rigid enough to where it doesn't just spool up like wire would do. So we're gonna just push this down through here now. After you push it down so far, it's not uncommon that you might have to get down here and reach around the panel to try to find your fish wire. And there it is. So now that we've got that, we'll take our wires here. Now on this side here, the driver's side, we only need the left turn and a taillight circuit. So we're gonna take the green wire here and we're gonna snip this right out of here. So I'm just going between the yellow and the green. I just gave it a little cut there 'cause the green wire has got to route over towards the passenger side. So we're gonna peel down just like that, that's probably good enough. Just enough to where when we pull this wire up, we can still reach our green wire to be able to route it over there. So we'll now take our remaining wires here. We're gonna just tape them to the fish wire that we ran down, so it's got some electrical tape here, just holding it along our fish wire, and then I'm just gonna tape it on there. And when you're taping it up, I highly recommend that you run enough tape on it to cover up the end here so there's no chance of that catching on something and folding over when you're trying to pull it up, Just like that, you can then pull our fish wire here to get this up here to our assembly. We're gonna just cut this off of here, doesn't need to be on here anymore. And you can actually take this fish wire here and run it down the other side because we're gonna have to be pulling wires up over there as well. So we're gonna be preparing that to make sure we can do that later, but let's go ahead and focus on these while we got them right here. So first I'll have to pull them up enough to make sure that I have plenty to work with. We'll then take each one of these, we're gonna grab our cutters and we're gonna separate each one of these. Alright, so now that we've got these separated here, we can start hooking them up. So we're gonna strip each one of these back. We'll then take our remaining connections here, which is the ones labeled RV brake and RV tail. We're just gonna pull both of those off of there. We're gonna take one of them and place it on the yellow wire. This is gonna be the one that will connect to RV brake on the diode. Here we go, and now we're gonna take the white and the brown wire, we're gonna twist these two together, and this is gonna attach to the remaining spade terminal. Double check your connection, make sure it's solid. All looks good there, so now we'll just take our wires and plug them into the appropriate location. So tail is gonna be the brown and the white wires. So we'll just slide those into place. And turn is our yellow wire there, so we'll just plug that in. And then we'll use some of the zip ties in our kit to give us a little bit of a cable relief here if we don't want our wires to ever get tugged, so we'll zip tie it to this factory harness here. And we're just gonna do right about like that. That'll give us plenty of release. Fold like this. We can snip off the excess. And now that we've got this side all connected here, we can reinstall our taillight assembly. Then our assembly, we'll just push back together, can you plug in your connectors there I should've pushed that lock tab back in, and then you can re-install your fasteners. So now we've got this side installed, we're gonna remove the passenger side, we're gonna get our fish wire routed down, and then I'm gonna wrap my wires appropriately over to that side. I'm gonna go ahead and get those routed over there now and then I'll show you the path I took to get them there. Now, when routing your wires across, there's two wires you got to route over there. You need to route the green wire and we need our taillight circuits to get routed over there. When we hooked up the taillight on this side, we hooked up the white and the brown wires together. The brown wire is the taillight circuit, so we're gonna use a small portion of this white wire jumper from that side over to this side. So what I do to help determine the amount of length I need to make that trip, I take the green wire here, and we did have to peel back some more, we're just pulling down to peel it back. And as I'm peeling it back, I'm bringing it across and I'm kind of angling it up 'cause I know this is where I'm gonna be routing it roughly. And this I know is gonna be plenty of length to be able to route over, to connect to my diode over here. So after I do that, I then take the green wire and I just fold it back down my wire and I'm just kinda running it down. And when I reach the end of my green wire here, that's where I'm gonna cut my white wire, so that way I'll have the same length of white wire to run from that side over to this side as my green wire. So I'm just cutting it right there. After you cut it, you can kind of fold it in half like this, and then we can cut in between the white and the brown, and that will let us separate it from the rest of our wiring here, so there we go. We've got that snipped at the location we want, so we're gonna take the white wire now and I'm peeling this back up to meet our green wire, and now we've got our equal length of green and white wire that we know is gonna be of adequate length to reach this side. The other end of our white wire here, I'd recommend just peeling back, just like an inch or so. We'll be hooking this to ground at a later point, but it's nice to be able to see where this is as we're wrapping the wire later, sometimes you can kind of lose where you had cut that portion, so if you peel it back, it makes it easy to find later. So now I'm gonna get these routed across and then again, we'll show you a path that I took to get it across here. So we've already got our wire cut to the right length, I went ahead and routed it across right here where this bolt is, this is where it attaches the rear bumper to the frame, so we pushed it above that, you can reach right above it, that'll keep it from falling down on our exhaust here. We then put it behind this plastic trim, you can just poke the wire in until it comes out the other side right here. And then once we get out the other side, we go up above that bumper attachment there to keep it away from this part of the exhaust. And then we use that fish wire trick that we did before to get this pulled up behind the passenger side taillight assembly. So we got our white and our green wire routed cross. We pulled them up using the same fish wire trick we did on the driver's side. After that, we stripped them back and put the spade terminals on them. We hooked the white one to the RV tail and the green one to the RV brake. The factory wire we cut on this side is gonna be pin three, so it's the same terminal location as the other side and the color is going to be white with a gray stripe. So it's just like the other side, we cut that wire, we crimped on spade terminals on one side, out goes to the assembly and then it goes back to the vehicle here. So now we're gonna get our wires routed to the front, then we've got everything hooked up here at the back. So you see your green, yellow, and brown, there is white further up the line there, so we route the rest of these wires towards the front. You kind of just use our factory wiring to keep everything out of the way. Make sure we go above our suspension here 'cause we want to avoid any moving objects like our suspension components and anything excessively hot like our exhaust. After we go up above the suspension here, we come out on the other side and we go down underneath our fuel tank. From there we head forward. This is the rest of the white wire. So we routed white wire across to bridge that taillight circuit. This is the rest that's going up to the front, we're gonna be hooking up to our six pole connector there. So for this guy here, we just need to attach this to ground so we're just gonna run it right into the bottom of the frame over here. So I'm just gonna kind of get myself a good amount of wire there, it's gonna reach where you want to put it. Trim off the excess, we can go ahead and strip it back. We'll then take one of the small ring terminals that comes in our kit. Slide that on there and then we can get that crimped down. From there, just like we did behind our taillight assemblies, we're gonna run our ground wire in it right up into here using self-tapping screw and eight millimeter socket. We'll just place our screw through the terminal and then just run it right into place. We don't want the wire to wrap around it like that so if that happens to you, go ahead and stop real fast. What you can do to avoid that is you can run the self-tapping screw in first and then pull it back out. But you have to avoid that wire wrapping around, we're just gonna put it in first now. Make sure it's nice and snug and then we can continue routing our wire forward. From here, we just stay underneath the fuel tank, but above the skid panel here, until we come out the front. Once we come out the front, we stay above the skid panel here, just routed all the way forward down this channel, so we come out the other side here. From here we route it up into our engine compartment because we do need to access this wiring for our supplemental braking system. Many of your braking systems are gonna require you to tap into your diode wiring for proper operation. So from here, we just use that fish wire trick again to pull our wire up into the engine compartment, and then from there, we'll continue routing it to the front. If your braking system doesn't tap into the diode wiring, you don't have to, and you can just continue running it all on the bottom. But again, most of those breaking systems do require this, so you just want to double check to see what type of system you have if yours requires it or not. Our wire comes up right here at the back next to the vacuum brake booster, that's where we went ahead and pulled it up and we zip tied it to the factory harness that goes across here to ensure it can't fall back down. From there, we just ran along side of our master cylinder here, the fuse box, the battery just kind of go in between those components. Once we hit the coolant bottle here, we turn a little bit towards the driver's side, zip tie it to a factory harness down there. And I did leave excess here where it runs along the batteries and stuff so we can kind of move this around, 'cause we're gonna be tapping into it here. So if you got, if it's pulled real taut, it's gonna be real hard to splice into this. So if you leave yourself some access and kind of feed it around some components like this, it'll make it easier for you to access it later. You have to still make it look kind of hidden. From there, once it zip ties to this point, we just take our hand and just poke it through an opening next to the radiator here at the front. And I just use one arm to poke it in and then with the other arm, I grabbed it here on the other side and it came out right here and then we just routed it over. And you can see here, we don't have the front fascia arm because we just got done installing our base plate. And that's the best time to finish up all of your other flat tow components like your diode wiring here and your supplemental braking system, because we're off the fascia the way, it's a whole lot easier to get this wire routed up here. So now that we've got our wire routed up here, we've completed all the rest of the connections there at the back. There we're things left, to hook it to our six pole connector here. But if we attach it here now, we're not gonna be able to install our fascia. so we're gonna go ahead and get everything completed, so we'll get our supplemental braking system done next, get that all done, then we'll get our fascia all trimmed out per our base plate instructions. We're now gonna go ahead and get it back in place. Extra set of hands definitely makes this easier. It's kind of a difficult fascia to get snapped in. Now there may or may not be trimming required on yours. Ours already had the whole cavity cut out like this. You may have a plastic cover there that has some bolts on the inside you can remove. Ours is a different design, so it doesn't have any of that. I'll just keep that in mind, you may need to remove a panel from this location. And once we get it lined up, we'll just push it back into place. And we'll do the same thing on the other side to get it snapped in. So now that we've got our fascia back on, we can go ahead and reinstall all of our fasteners in reverse order, and we're also going to trim out this area here and finish wiring up our components here at the front. So now we're gonna get this connector installed here. So the first thing we needed to do is trim out our fascia so it'll fit, we've got that all re-installed here. So if you see here, this is the large area that needs to kind of pass through for our wires to poke through and it's not gonna fit. We really just need to trim out this middle section here though, so we're just gonna use our snips and we're gonna basically just cut here. I kind of cut this out right in here. So we'll just snip right there, snip there, snip here, here, and then we just need to get these middle sections out of here so we can trim there and there. Let's check our fit. It looks like we might need to take out just a little bit more right here at the top so we'll cut off this little groove. Okay, let me double check our fit once again, and that looks and feels pretty good right there, so that should work out fine for us. Should also be able to pull through any buyers that we've run here at this point. We haven't re-installed the under shield portion of this yet to ensure that we can still pull this through and everything. All right, so now we've got to all of our wires here. A couple of these wires aren't for this connector, these two here are for the breakaway switch for our supplemental braking system. We're gonna be mounting our breakaway switch in this area as well, so they're gonna hang out right here, but we're not gonna be connecting these to our actual connector that we're about to install here. So we'll just separate these out and I'll set these off to the side like this, we'll just kinda send them over this way so they're not bothering us. And then these are the ones that we're gonna connect to our switch. We've got our diode wiring connections here, and then our customer also wanted a charge line kit, so we'll be adding that to it as well. This does not come included with your diode wiring, you can get this from Roadmaster here at Etrailer. So that way, when you're driving your motor home, pulling your vehicle behind you, it keeps the battery topped up for you so it's ready when you get to your destination. So the first thing we're gonna wanna do is get rid of some of this excess, we got way too much excess here. I always like to leave some just so that way for future accessories we wanna add or potentially any repairs that may need to be done, you know, many years down the road, we can be able to do that easily. So we're gonna just kind of come out here and that's enough room here for us to be able to kind of access this at a later point, so we'll just get rid of the rest of that there. Each of these four wires now, we're gonna take our snips here and cut right in between each of the wires so we can separate these from one another. Here we go, it all peel back. All right, we're gonna be stripping these here in a minute, but I found that it's a little bit easier to slide your boot on before you strip them. If you strip them, the strands of the wires like to get caught inside of it, just makes it more difficult, so just pull the boot off the back of your connector. Any wires that you're intending on hooking to your connector, slide through your boot and we can just push that right up there for now, just cause it has to be on there or else we won't be able to install it later. So now we can go ahead and strip back each of those wires. All right, so now we've got all of those stripped. I like to twist each one, it just makes it poke into the connector a little bit easier. Each of our connections here are labeled on the back of our switch. They're a little bit difficult to see because the actual labels are right underneath where the screw is. So you kind of got to look at it from an angle here on the side, and we're gonna look for GD first. GD is ground and I always like to start with that one. All right, so right there, I just like to start with that one. If you need to, you can fall a little bit more back on these. I'm just gonna get a little bit more out of it. Then we're gonna take our wires now, just poke them into the appropriate slot, so GDs right here, that's our white wire just pokes in and then we can tighten this down. Next LT, that's the left turn, that's our yellow wire. So that one we'll just poke in, and then we're gonna tighten it down. And I'm actually gonna shorten the length of these wires a little bit. It looks like the connector has changed just a little bit from its previous design and the shafts are slightly shorter in their depth than the previous ones were. So we stripped off more than we really needed to, so we're gonna trim that down 'cause we really don't want any strands sticking out of the top, kind of like what you're seeing on the light wire here, how we got visible strands, we're probably gonna go back and turn that one just a little bit more as well 'cause we don't want to see that. So now we're just gonna poke this in and that's what we wanna see, the yellow wire, the jacket for the yellow wire flush up against the top of our screw hole there. That way there's no chance of the wire potentially being and grounding out or shorting to something else. Next is RT, that's right turn. That's our green wire, so I'm gonna grab that one. And I'll also trim this one down just to make sure we don't have any issues. Put that into the slot labeled RT. If your wire strands curl up like that, go ahead and pull it back out and unloosen your screw just a little bit more because even a single strand that comes out of here could touch on another post and could potentially activate lights that you don't wanna activate, cause shorts and a lot of other strange problems to occur. Next is S, we skipped that. After that is TM for our taillight circuit, which is our brown wire. Once again, we're gonna turn this a little bit. And then lastly, you've got that red wire there that's for our charge line kit, we're gonna slide that into our center post. And then the center post looks like it's quite a bit deeper than the other ones, so we'll see if we do or do not need to turn this one. Yeah, we'll have to trim this one just a little bit as well. All right, so now we've got all of our connections made, we're just gonna double-check our circuits, let's say the yellow wire's got a strand sticking out, we're gonna address that, get rid of it, and I'm gonna trim our white wire down just a little bit more. Looks like our brown wire also has a stray strand so if you see any of that, we're gonna clean all that up to make sure we don't have any of that. So now that we've got our connector fully attached. We can use some dielectric grease and we're gonna be pretty generous with our dielectric grease here to coat the back of this, to seal it up to prevent any moisture from entering it, so we can ensure we've got a long lasting connection for many years to come. Now we've got it all cooped up, take your dust boot, just slide that down over it. And then I like to take electrical tape just to ensure the dust boot doesn't like to slide off of there or anything, and we're just gonna seal this up on each side. Also helps trap in that dielectric grease. So now you can round up your connector to mount it up, it simply just lines up with your base plate connection point if you're using a Roadmaster base plate like we are. And then the screws that come included with your base plate, just line right up, eight millimeter socket. We'll run these right in. So now we've got that complete. Your diode wiring, you're ready to test that out. You do also get this bracket included in your kit. If you don't have a base plate. that provides mounting locations, you can use this to like run self-tapping screws into the bottom or something to mount it up. We are actually gonna be using this bracket, but not in the way that it's intended for running our six pole. We'll be using this to give us a mounting location for our breakaway switch so you do get some extra pieces in your kit that you don't necessarily have to use, but you can often repurpose those for other things on your flat tow setup. And that completes our installation of Roadmasters Smart Diode Wiring kit for our 2021 Jeep Cherokee..


Info for this part was:

Employee Andrew K
Video by:
Andrew K
Employee Schuyler H
Video by:
Schuyler H
Employee Jeff D
Installed by:
Jeff D
Employee Joshua S
Video Edited:
Joshua S
Employee Jacob T
Video Edited:
Jacob T
Employee Dustin K
Video Edited:
Dustin K
Employee Chris R
Video Edited:
Chris R
Employee David F
Test Fit:
David F
Employee Bradley B
Test Fit:
Bradley B

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