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SMI Stay-IN-Play DUO Braking System Installation - 2018 Jeep Cherokee

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How to Install the SMI Stay-IN-Play DUO Braking System on a 2018 Jeep Cherokee

Speaker 1: Today in our 2018 Jeep Cherokee, we're going to be installing SMI Stay-IN-Play DUO Supplemental Braking System, part number SM99251. The Stay-IN-Play DUO is going to be a braking system that permanently installs on your vehicle, so when you're pulling up behind your RV, it'll apply the brakes, making it feel like you're not hauling nearly as much of a load.It features a proportional braking system, so when you're sitting at a stoplight and you've got your foot on the brake, only the brakes on your RV are going to apply. There's an inertia switch located inside the control box that detects movement, so if you're traveling at any speed, it'll apply the brakes harder depending on that inertia.You're driving down the highway and you're about to get to your destination. You merge off, hit the brakes, and the brakes inside your vehicle apply using the cylinder attached to the pedal. You come to a stop and they stop.This is going to be a permanent installation, so your vehicle's always going to be ready to hook up to your RV and go to your next destination. Your control box will be mounted on the inside to easily switch the system off and on.

The proportional braking system can be adjusted using this sensitivity knob. Simply unscrew the knob and adjust it up for less sensitive, which means that it'll actuate with less inertia, and move it down for more sensitive so it activates with less inertia. Once you've found that sweet spot, just tighten the knob back up and you're ready to go. The actuating cylinder will attach to your brake pedal and will pull the pedal in when you go to stop.There's an LED indicator located on the backside of the mirror. This illuminates when the brake pedal is pulled and since it's tied directly into your vehicle's brake light switch, you know the pedal's being pulled when the light illuminates.

This'll give you peace of mind because you'll be able to look in your RV's rear view camera and verify that the brakes are being applied.The operating unit is tied into your vacuum system on your vehicle. When comparing this one to other removable units that are just placed inside the vehicle and removed when not using it, it has a much smoother brake operation because it's tied into your vehicle's vacuum system, so it applies vacuum to your brake booster, allowing the system to pull the pedal much smoother and easier.Also included with the kit is a breakaway switch. This is an extra layer of safety, so in case your vehicle does become disconnected from your tow bars, the chain'll pull out the switch, applying the brakes in the vehicle. This is one of my personal favorite braking systems. It's one of the easier permanent systems to install, so that way, it's going to be on your vehicle all the time.

You don't have to fidget with taking things in and out and when you compare it some other styles, such as the Invisibrake, while that system is a cleaner install, it'll be more hidden, it is a lot more work. When comparing it to the Air Force One, you have to do modifications not only to your vehicle, but also to your RV. I like that the SMI is all located on the vehicle and it's fairly simple in comparison to the others.We've already gone ahead and mounted the main components. I'll show you how I've mounted those so you can get those mounted, and then we'll get everything hooked up. We went ahead and mounted the operating unit right to the top of our fusebox.

To make this work a little bit better, we took some of the hose provided in the kit and we cut off about a half inch for spacers and then used zip ties to secure it. Those spaces are necessary due to the bolts located underneath the bottom side here so it doesn't hit on your cover and cause it to warp or bend.This is where we mounted our breakaway switch. We mounted it right to the bracket that we had used in our diode wiring kit for our six pull connector. We attached it to the bracket using the provided bolt flat washer. We then go through the breakaway switch, the bracket, and the nyloc nut on the backside.We installed our control unit right to the lower left kick panel on the driver's side. This way, it's still accessible. You do want to make sure you give yourself enough room to where you can still open the hood latch when you install it. Now you can easily turn it on and off and make your adjustments. It's still tucked out of the way so you don't have to worry about hitting it with your foot.We installed it using the two screws that came with the control unit. They simply run right into the panel. I already removed the panel and checked behind it and there was no circuits or wiring behind there, so we we're able to just run it right in with no worries. We mounted our brake cylinder here onto our brake pedal. We did have to upgrade to longer bolts. You can pick up some longer bolts here at The longer bolts we're necessary due to the extra width that this brake pedal has versus your conventional brake pedals.We tightened the bolts by hand using a 3/8" socket. We just held the socket in our hand and tightened 'em down. You don't want to over tighten these and you'll have to go back and forth between volt to volt, simultaneously tightening 'em down back and forth so it tightens down evenly.We mounted our anchor here just back from the brake pedal. This hole was already cut out here and beneath it, you'll see some black tape. I went ahead and pushed through that tape so I could verify there was nothing behind it. Also, there's a grommet located behind this tape that you can push through because we can use that to run our wiring and hoses as we install the kit here in a little while. We mounted the anchor just above it, so we did have to cut a little bit of it out using a razor knife. That way, we got our nice straight angle so when it pulls our pedal, it's not going to cause any damage to the back of the cylinder or the cable. It's very important that it's mounted in a straight line so that way, when it pulls it, it pulls it straight.We mounted it using the self-tapping screw provided in the kit and tightened it down with a 3/8" socket. Then we adjusted the appropriate length of the cable and tightened it down using a 5/32" Allen key. Now, when you tighten this down, you just want to tighten it until it holds the cable. You don't want to go too tight, as it can cause damage to the cable. When you're all done, you want to have just a little bit of play so you know it won't cause any binding on your brake pedal, but it'll still be able to actuate fully and apply the brakes when it's being pulled behind your RV.Once you've got all your components mounted, we'll go ahead and take our wiring from the inside on our control unit. We're going to run that to the outside. We're going to go ahead and use that grommet that was located just below our anchor point here. Go ahead and take your wires, kind of straighten 'em out a bit and poke it out through that grommet. If you need to remove the grommet, just simply push on it. It'll fall out, and then you can pick it up below the vehicle. Before we go underneath to grab our wires, we are going to do a fish wire trick. We're going to use a piece of airline hose. We're going to feed it down through where we want these wires to be routed and that way, down below, we can attach to this wire and pull 'em back up, making it nice and easy and a more desirable routing path than what you can do with just the bare wires. We're feeding it down just behind the fusebox, between it and the ABS unit.You can stick your hand just above your steering linkage and pull that wiring down. The grommet's located just above that. We then can take our pull wire that we ran and connect it to the wiring and pull it back up. Go ahead and tape this up and we're ready to pull it up. Now, if you we're having difficulties accessing the wiring and the hose, couldn't get your hand quite up in there, if you take off the under shield here, you'll have a lot more room to get in there. Now, we'll just pull our pull wire up and bring our wiring up to where we can hook it up easily.Before we hook everything up, we're going to make sure we've got all the wiring routed to a central location to make it easy to make the connections. We'll take our breakaway switch wiring and we're going to just route it just as we did with our diode kit wiring. We're now going to begin our connections. We're going to start with the yellow, green, and white wires from our control unit on the inside and tap into the yellow, white, and green wires from our diode kit. To begin, we are going to need to separate some of these wires. The only wire we will not be cutting is our brown wire.Once you've got all your wires cut and separated, we're going to take our control wires, run those up 'til they're about the right length, and then trim all those. Now, we're going to strip back the ends of each wire on both our control unit and our diodes. Now we're going to connect the wire colors from our control unit and match those to the wire colors on our diode wiring. We're going to take our greens, twist those together, and crimp on a butt connector. Now, the butt connectors provided in the kit are a little different than this one. We've upgraded to heat-shrink connectors because they are going to live outside the vehicle. That way, it'll keep these connections sealed and prevent moisture and corrosion from getting in there. We'll then do our yellows and we'll twist our white wires together. Now, our white wires are going to be similar to the others, but we are going to go ahead and run a redundant ground on those.We're taking our control unit wire and splicing it into our diode wiring, and on the other side, we're going to take some of that excess white wire that we just cut off of our control wire, strip back both ends. We're going to twist this side to the other side of the white wire from our diode wiring and connect it to the white wire on the butt connector here. We can then go ahead and connect the yellow to the yellow butt connector. Then after you finish connecting the yellow, we'll connect the green.Then we took the other end of the short wire that we added on and we crimped on a small ring terminal. You can use the ring terminals in the kit. However, we've upgraded to a larger yellow size so we can mount it right to the ground stud located over here. Remove the nut, slide on your white wire, and then reinstall the nut. We used a 10-millimeter socket to remove and install the nut. We'll then take the red and the black wires from our control unit and connect those to the red and black wires from our operating unit. Go ahead and route those where you want them. I do recommend you leave some excess on your operating unit wires so you can still take your fuse panel cover off and on without having to remove the whole thing. We're going to come to about here. That way, we've got about a foot-and-a-half of excess to get that on and off. We'll cut both those wires and we'll go ahead and do the same with our control unit. Now strip back each end of each wire.Connect your red to the other red using the blue butt connectors in the kit. Now, we did upgrade again to heat-shrink connectors here, then connect your two black wires. Now we'll connect the blue wire from our operating unit to the blue wire from our breakaway switch. Again, you want to route it around and make sure you've got a little excess so you can get that fusebox cover off. Cut off the excess from the operating unit. Strip back both ends and connect them together with one of the blue butt connectors.Our last two wires, the brown and the orange, are going to be connected together and to the battery. We'll connect them to the battery using this fused harness in your kit. Go ahead and cut the fused harness in half and strip back both ends. Then you'll connect one of the ring terminals in your connect to the end. The kit only comes with blue ring terminals, so you may have difficulty getting it on there. We upgraded to a yellow to make it slide on much easier and ensure that we're going to cover the complete width of the wiring. Then on our other end, we're going to connect one of the yellow heat-shrink connectors.Then before we hook up the other end of our butt connector, we're going to go ahead and connect it to the battery. This way, we can ensure that we've got the appropriate length that we want for our fused harness here. Go ahead and slide that ring terminal on the post, put the nut back on, and tighten it down with a 10-millimeter socket. We can then figure out how much length we want to have and cut those wires to length. We're going to go ahead and use the full length of the orange and black wire. We're going to trim down our brown wire. Now strip back both ends of the brown and the black and orange, twist the brown and the orange wires together, and connect 'em to the other end of the yellow butt connector from our fuse harness. Now if you upgraded to the heat-shrink connectors, go ahead and take your heat gun and shrink all those down.We're now going to tap into our brake booster vacuum line. That'll connect on this hose here and our brake booster vacuum line's located here. We'll have to cut this line. You want to find a nice straight location where we'll tap a T 00:13:49 fitting in. This is a pretty good straight area, so we'll go ahead and cut this hose here right in the middle. We've got a pair of hose cutters here. If you don't have a pair, you can pick one up here at This is great because it cuts it nice and flush and even.Once you find the center, go ahead and cut the hose. Now, when you cut this, if you've ran the vehicle recently, it might make a little sucking sound. That's just the vacuum being released. It's not a big deal. To get our T fitting to tap in line, we are going to need to cut some of our hose and use that to connect it to the plastic brake line. We'll cut back a couple inches. That'll go to one side of our T fitting. We'll cut back a couple more inches. This'll go to the other side. Lastly, we are going to cut back just a little bit more as this is going to allow us to connect our check valve in line.Slide one of your hose clamps over the end of your backing brake line, then slide your T fitting that we made onto the hose. If you're having difficulty getting it on, a little bit of soapy water or lubricant will help it slide on better. After you've got it slid on, slide your hose clamp back and tighten it up. You can tighten this up using a flat bladed screwdriver or an eight-millimeter socket.Now we need to insert our check valve, black end into the hose. This end's going to go towards the engine. This end will then go into the hose T fitting that we made here. This end will plug back into our vacuum line. Now, you don't want to put too much stress on this hose, so in order to get this back on, we are going to trim off a little bit more so we can slide this on. Slide your second hose clamp on and now you'll want to connect this end onto your hose. Again, if you're having difficulties, a little soapy water makes it a little easier, and just slide that in, right into your hose.Once you've got it slid on, go ahead and tighten down your hose clamp. Now we'll take the rest of the hose that we have and we'll line it up to make sure that we can get 'em on there and that we're not going to be putting too aggressive of a kink in the hose. We're going to give ourselves a little bit of excess on each side like this so it has a nice smooth curve. We'll go ahead and then cut it to length. After you've got it cut to length, slide your hose on one end, feed it into the other end. Here, you might have to get a little creative with how you've twisted it to get it to angle correctly.Now take the black tubing in your kit, push it down in the hole where we ran our other wires. Then we'll use our same pull wire trick under the engine compartment to pull this black wire up into that engine compartment. We'll just pull that up, and now we can connect it to our operating unit. Now we can take our air hose that we ran in, make a little loop so we've got some excess, and also to allow the fuse cover to come off easily. Then just plug it right into that fitting there. Make sure you're all the way in. I like to go in and out just to make sure it's all the way in there. Then we can take our excess that we've got here, find out about the right length. That looks about good there. Cut it and press it into our brake pedal's actuator. Again, you want to make sure that it's fully seated, pushing in and out.We can now take our LED indicator and attach it to our mirror. This'll let us know when our brake pedal on the vehicle's being depressed. Peel back the adhesive backing and apply it to your mirror. You'll want the wire end facing up towards your headliner as we're going to be taking this wire and poking it right up into the headliner. Continue to feed it up into the headliner, working your way down to the A pillar 00:18:48. In order to feed it up in there, you may need to pull small portions of the headliner away from the A pillar. Run the wire around. After you've got it past your headliner, just feed it down your A pillar, just pushing back on the weatherstripping as you're working it down. Once you've got it worked all the way down, just feed it over past your panel this way.In addition to installing the braking system, we're going to need to install a brake light relay. We need the brake light relay to prevent the vehicle from overriding the turn signals that's coming from our RV. We've got our tester hooked up, which simulates an RV providing a brake signal. As you can see, our left tail light's on, but when the brakes are applied in the vehicle, the brake lights come on and we don't want this. We want only the appropriate brake signal to come on from our RV when we're pressing 'em. We don't want the vehicle signals overriding them. We'll accomplish this with part number RM-88400.We're now going to install our brake light relay. We've already identified which brake light wire that will be. That's going to be the green wire on our switch, but before we tap into it, we're going to remove fuse 77 in our under hood distribution box. This'll disable the circuit so we don't cause any SEF deterrent 00:20:17 issues. We'll reinstall this once we've completed the brake light relay installation.We're now going to need to disconnect our brake light switch connector from on top of our brake pedal. It's located at the very top. We've disconnected our brake light switch. The wire we're going to be tapping into is the green wire. You can see here that that is the furthest to the right. The green wire next to it has a yellow stripe. That's the one we will not be using. We'll be using the solid green. Once you've got it disconnected and pulled down, we're going to want to cut back some of this sheathing here so we can access the wires and splice into 'em.Now that we've got some peeled back, we'll go back a little bit from our switch and we're going to cut the green wire. Then we'll strip back both ends of our green wire. Now we'll connect a yellow butt connector to each end of that green wire. Now, your kit did come with blue butt connectors. We've decided to upgrade to the yellow just to make things a little easier because some of the wires are going to have multiple wires going to them and it can be difficult to get them fed into the blue.We'll now hook our blue wire and the red wire from our LED indicator together by twisting 'em together and crimping 'em to the connector side yellow connector. Now typically, you would just push this into a crimp connector and crimp it down, but since we do have to pair it with another wire in order for it to fit properly, we're going to have to cut this off. We'll then strip it back and twist it together with our blue wire. Push the blue wire with the red wire into the connector side of the green wire.We'll then hook our black wire into the other side, which is going to the module side of the green wire. This is the black wire coming from our relay harness. Now the black wire from our LED indicator is going to need to go to ground, so is the white wire from our brake light relay harness. To get those connected to a ground since they're kind of so far apart, we're going to be connecting them together and then running 'em there to a single grounding point. Once again, we are going to cut this off just because we need to twist it into a pair of wire and that'll make it easier to do so.We'll be twisting this with our white wire from our harness and connecting those with the yellow butt connector. We're then going to take some of the extra white wire that we had from our diode wiring kit and we're going to crimp this onto the other end of the butt connector. This will allow us to extend this wire to reach a grounding point. We can now plug our relay in and then tape up our wiring and plug our switch back in. The only wire left to run is the power wire to our relay and we're going to be tapping into the RV's tail lamp circuit to do so.We're now going to use some of the red wire that comes in your SMI Braking System kit. We're going to run it through the grommet and run it up into the engine compartment so we can tap into our brown circuit for our tail lights from our RV and connect it to our wire. Go ahead and poke it through. Before we run it up into our engine compartment, we're going to connect the red wire to our relay harness. This way, it will prevent us from accidentally pulling the wire too far and having to route it again. We'll use the pull wire trick again to get it up into our engine compartment. We've got our wire routed up. We're now going to tap into our brown wire here. We'll cut it, strip back a little from both ends, strip back a bit of our red wire, and we will splice it in with our brown wire. Then heat-shrink down your butt connector and zip tie everything up.All that's left is to run our ground wire. Now you can attach this to any ground stud that you see, run a self-tapping screw into the body, or what we're going to do is we're going to splice it into our white wire here since this is already a ground wire. We'll just splice it right in using one of the butt connectors. We'll cut it to length. We'll cut our white wire and we'll connect these white wires together. Connect it with a butt connector and then connect the other end of the white wire to the other end of the butt connector. Now you can clean up all your wiring and make everything nice and neat.We can now reinstall our fuse back into slot number 77, then install the fuse provided in the kit into the fuse holder that we previously installed. After you've got everything tidied up, don't forget to reinstall your grommet. This is probably done underneath coming from the driver's side tire up over the suspension. You can reach right up to that firewall where that grommet is, get it pushed back in. You may have to cut some slits in it to get it over, cut out a little bit, and then use some silicone here to seal it all back up.Now to make sure everything's working properly, hit the "on" switch on your control unit and pull the pin. You want to make sure that it's pulling the brake pedal straight, right into the anchor point that we had mounted earlier. If it's pulling straight on the cable and everything's working properly, you're good to go. Now it's time to reinstall the fascia 00:27:00 and anything else that's been removed. Once you've got everything reinstalled, hook your vehicle up to your RV and get an extra person to apply the brakes in the RV. That's going to activate the brakes in your vehicle. However, we don't want this while we're sitting still. This system's supposed to act proportionately, so we'll need to adjust the sensitivity while we're on a flat level ground. With somebody holding those brakes, unscrew the knob, slowly go upward until the brakes are no longer being applied. Once they're no longer applied, we find that spot, go up an additional eighth of an inch and then tighten it back down.When you go back on with your bumper, you are going to need to make some additional trimming around your six-pull connector and breakaway switch. This may vary slightly on yours if you have it mounted exactly as we have here.In summary, to get our 2018 Jeep Cherokee towed behind our RV, we used Roadmaster's EZ5 Base Plate, Roadmaster's Tow Bar Wiring Kit, SMI's Stay-IN-Play DUO Supplemental Braking System, Roadmaster's Break-Lite Relay, Roadmaster's Falcon Tow Bars, Roadmaster's safety chains, and Roadmaster's High-Low Adapter.That completes our installation of SMI's Stay-IN-Play DUO Supplemental Braking System on our 2018 Jeep Cherokee.

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