SMI Air Force One Braking System Installation - 2019 Jeep Grand Cherokee

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How to Install the SMI Air Force One Braking System on a 2019 Jeep Grand Cherokee


Hi there Jeep owners. Today on your 2019 Jeep Grand Cherokee we're going to be taking a look at and showing you how to install Demco's Air Force One supplemental braking system. Your supplemental braking system is one of five main components you'll need when flat towing your vehicle behind your motor home. A supplemental braking system will apply the brakes in the vehicle when you hit the brakes in your motor home to help it come to a nice seamless stop.In addition to your braking system, you'll also need your base plate, which is the connection point for your tow bar on your vehicle. You'll need your tow bar, which is the connection between your vehicle and your motor home. Your safety cables, which is a supplemental connection in addition to your tow bar.

And lastly, you'll need your diode wiring, which takes all the lighting signals on your motor home, transfers them to your vehicle so that way the lights at the back will illuminate so people behind you will know your intentions when going down the road.The Air Force One is a truly proportional braking system using the air pressure from your air brakes on your motor home to apply the cylinder here located on our brake pedal. So when you hit the brakes from your motor home, air pressure will go through the system and extend the cylinder pulling it with the cable that's attached to an anchor on your firewall. Being a proportional system, means that your vehicle is going to stop similarly to the way your motor home stops because the harder you hit your brakes in the motor home, the harder the brake pedal is going to apply here inside the vehicle.So here we are in our motor home and when I press the brake pedal here, you'll see it apply on the brake pedal in the towed vehicle behind us.To inform you that your system's working properly, there's an LED located on the backside of your mirror and you can often see this through your rear view camera in your motor home. This light will only illuminate when the pedal is actually being depressed in the vehicle. So you can see there that when we apply the brakes, the LED comes on, we release the brakes, and the LED goes off.The air's transferred to the cylinder on your pedal through our operating unit here.

The operating unit also applies vacuum to the brake vacuum system to ensure that when it's applying the brake pedal, we've got vacuum assist to apply the pedal just like we would when the vehicle was running. It also acts with our breakaway switch to apply the brake pedal in the event of a catastrophic disconnect.At the front of our vehicle, you'll see our breakaway switch and the switch is designed in case of a catastrophic disconnect to have the pin pulled, which would then activate our operating unit located under the hood, which would send stored air pressure to the cylinder located on our brake pedal, applying it to help our vehicle come to a safe stop.Now a lot of people out there are wondering, "Well do I even need a braking system" So in addition to it keeping you DOT compliant and legal in all states, I'll give you a scenario of why it's important. Let's say you're in a very hilly area or maybe mountainous area and you're coming down a long steep grade going downhill. If you didn't have a braking system, the weight of your vehicle would be pushing on the back of your motor home and your motor home's brakes would be doing all the work. Over a long period of time going down this hill, that can cause the brakes on your motor home to start to heat up.

As the brakes heat up, the brakes will begin to fade and you'll lose braking power as you're going down the hill. By having a braking system inside the vehicle, that will relieve all that weight that's on the back of your motor home, pushing it down the hill, keeping the brakes nice and cool so that way they'll act just like they would as if you weren't towing, allowing you to continue on without a hiccup.Since this system uses the air brake system on your motor home to activate the braking system installed on the vehicle, we've got a few components installed on our motor home. There is a reservoir tank that's installed on your motor home and you'll see a couple of outputs and inputs here. The big purpose of our tank here is to have that storage inside of it and to send it to our connection point at the back of the motor home where we can get our connection to our vehicle. And what you see here is that connection point on the motor home.

The braking system does come with the included air umbilical cable that'll run from the motor home's connection point over to the vehicle's connection point.We'll begin our installation by mounting all the major components. The biggest component that we're going to need to mount is our operating unit here. We've mounted it directly to the top of our fuse box and we mounted it to the fuse box using zip ties by just drilling some holes. So set your unit on there. You'll see there's four holes in your unit. Just go ahead and mark those holes with a paint stick. Drill those out and then you can run zip ties through and loop them back onto their self. You can see here how our zip tie runs through the case, comes up out the holes and runs across the top. We did that on each side to hold it in place.Outside the vehicle at the front you'll need to mount your breakaway switch and your male air fitting and we just attached these to the base plate's six pole connector mounting bracket. There are holes on the side so when we ran the bolts through we just put our breakaway switch on one side and then on the other side we used a small piece of metal that came in our kit and just attached that to our six pole and then attached the male connector to that using the included screws.Here on the inside of the vehicle we mounted our actuating cylinder to the brake pedal. The nuts just come right off. You can take the other piece of metal that runs down it and clamp it around your brake pedal like you see here. When tightening these nuts down, I recommend just tightening them by hand. What I do is I just use the socket with no ratchet on it and I just twist the socket by hand to tighten these down because if you over tighten it you could potentially damage it and it really doesn't need to be nearly as tight as you think it does. You'll find out when you're tightening it by hand and checking it, you'll see when it's nice and snug to where you're not going to knock it off.On the back of our cylinder, we have a cable coming out the back with an anchor point on it. The anchor point just attaches to the firewall using the included self tapping screw. Once you've got that mounted up, pull the slack out of your cable and then use a 5/32nds allen key to tighten up the set screw located on top of your anchor. I recommend that you tighten it down until it's about flush with the top of the anchor. If you over tighten it, you could potentially damage the cable and I found that flush is pretty well the right amount of tightness.Now we can start making all of our connections. We'll need an airline to route from our unit here to the cylinder located on our brake pedal. So we're going to route that, that's the air out. So if you're going to just poke that airline into the quick connect fitting here, and then from there we routed it down. We did drill a small hole through this plastic piece here to route our hose through. And then we went through the grommet there, which comes out on the passenger side in the lower kick panel area.I've got the airline pulled down, it's resting on top of the kick panel there, the cloth kick panel. And we just pushed it behind the center console. If you just push it over towards the driver's side, it'll slide down over towards your driver's side. It'll then come out on the other side here. And again, we just ran it on top of this panel and we ran it over to our cylinder here and then it just plugs into the quick-connect fitting.Now before we plug it into this fitting here though, it's a good idea to use your airline as a pull wire and take the brown wire that comes in your kit and we're going to route it pretty much straight from the same location on our box on the outside over here to our cylinder because it's going to connect to the small sensor that you see here on the side.The system also has a monitor light located on the backside of the mirror. The monitor light is turned on using the trigger sensor located here on our actuating cylinder. The LED light located on the backside of the mirror has two wires, a black and a red. And our trigger sensor has three wires, a black, blue and a brown. The brown just connects to the brown wire that we routed in, that's our power wire. The black wire from our sensor connects to the red wire from our LED and then the black wire from the LED connects to the blue wire from the sensor. And you can see here we used a triple connector because we also need to have ground. So we've got the blue going into one, the black from our LED going into the other, and then there's another black wire that we just ran back to the firewall and used a self tapping screw to attach for ground.The monitor light just sticks on the backside of your mirror. Whenever you're sticking it on there, you just want to make sure you don't cover up any sensors such as like a daylight sensor. So now that we've got that stuck on there we just tucked it up on our headliner, just poking that wire in. Once we get over to the pillar here, you can just pull this out a little bit to tuck the wire in around that and then we ran it down the side of our pillar going all the way down. To make it easier to get it to run down the side of your pillar you can pull the weatherstripping back. It just simply pulls off if you need to get it off. Just get your hand up in there, you got to get a good grip on it and then you just pull it away like that. So you can just do that all the way down to make it easier to route your wire in there.You can see the black wire here where it routed down. Just continue following that down and then push your weatherstripping back on once you've got it down. We came all the way down to this plastic piece here and then you can actually just pull this plastic piece out a little bit like this with your finger and you can poke the wire along that so that way we can come out here just above our under shield and this is where we'll make all of our connections.The brown wire is going to go here and it's going to connect to a fuse harness located at our battery positive post here. Now we do have an additional brown wire, which is the same brown wire that comes in the kit. We just cut a small length off of it to run to our breakaway switch located in the front. You can see how we've got two brown wires here to the same butt connector because both of these brown wires need power. The other one runs here, it runs down through, follows our wiring up towards the front and we make our connections to our breakaway switch here.The brown wire is going to connect to the orange and black wire coming from your breakaway switch. The blue wire coming from the breakaway switch will connect to the black wire coming off of your operating unit. Your operating unit has two black wires coming out of it. It doesn't matter which wire you hook to the blue wire. The other black wire is just going to run to ground and we just ran that straight over to the ground stud located here just to the passenger side of our operating unit.We'll now finish up our airline routing. The air in is going to route from the quick connect fitting here up to the male fitting located at the front of the vehicle. And we got there by just following our breakaway switch wires. You can go down through this paneling here and once you get behind your grill it's all wide open, you can kind of see through the grill there. And it just runs down and pokes into the backside of our male connector there.Now we can hook in our vacuum line. This is the larger hose that comes in your kit. So coming from the vacuum port you'll need a small piece and then from that small piece we're going to go to a check valve. Make sure that you have the black side of the check valve facing towards your operating unit and the clear-ish green-ish colored side facing away from the unit. We then drilled a hole through the plastic here, routed our hose through, and then we just followed all the way across over to our brake booster on the driver's side.This is your factory vacuum brake booster line here located next to your brake fluid reservoir. We cut the brake vacuum line here just to the inside of our brake fluid reservoir. From our factory hose, this is the hose going down towards the engine here, we plugged in our check valve with the black side facing towards the engine. We then cut a small piece of hose there off of the hose that comes in our kit and connected that to the other side of our check valve. Then on the other side of the short hose is our T fitting that comes in our kit. The T fitting is just going to plug into the small section we cut. The other side is going to plug back into our factory hose and the T that's pointing towards the center of the vehicle connects to the line that we routed all the way over to our operating unit.We'll now move on to the RV side of the installation. On your RV we need to mount our air tank and our female fitting. Our female connect fitting we mounted on our hitch just using a couple of self tapping screws and running it straight down into the hitch. On the back side of our female fitting we routed an airline hose over to where we've mounted our air tank.We've mounted our air tank in one of our rear side compartments and then you can mount your tank wherever you'd like. It's best to mount it in a location where it's going to be out of the way and it's not going to get damaged and one of your back compartments is really one of the ideal locations.The airline that we routed from our female quick connect fitting at the back connects to the 90 degree fitting here on our tank.We now have two more connections we need to make to our tank. We'll need to connect our air supply to this side of our tank, and our metered air here. We've got our metered air that we tapped into using the included T fitting here, and our supply air over there.Now the location where you're going to tap into your air brake system is going to be different depending on your motor home setup. So really what you need to look for is there's two different types of airlines for the system. You need your supply air, which has air pressure on it all the time, and you need your metered air, which only has air coming out of it when the brake pedal is depressed. The way I'd recommend checking these is to first drain all the air out of your system, you can do this by pumping your brake pedal, hop underneath, and then disconnect one of your airlines. Another thing that you can look for is when you're disconnecting the airlines is you're looking for a size that's going to be similar for your fittings. You've got the smaller three-eighths line here for your metered air and then you've got your larger diameter hose there for your supply air. So if it looks like it's going to fit into that T, there's a good chance you've got the right hose.Once you've got that disconnected, have an assistant start the motor home to build air pressure back up. If you're checking for supply air, you should feel air pressure almost right away because the compressor is going to kick on and try to pressurize the system, but it's not going to be able to because you've got the supply air hose disconnected so it's going to be leaking out of there.When doing your metered air, you're going to do it in a similar fashion. You drain the air first, then have an assistant start it once you've got it disconnected. And while they're building air pressure up, no air should be coming out of it, and then when they press the brake pedal, you should then feel air coming out of it and then you know you got your metered air.Once you've tapped into both of these lines, you'll just use the airline that comes in your kit and route it back to your air tank. Depending on the length of your motor home, you may need additional airline. You can purchase that here at etrailer.com. I've already showed you when we we're back at the tank where your metered air would connect and also where your supplier would connect, so just connect it to those ports.Now that you've got all your connections made, we can hook up our braking system. Use the coily cable that comes in our kit. The male end is going to connect on our motor home side and the female end is going to connect on our towed vehicle side.Then we'll hook up our breakaway cable, that's going to attach to your breakaway switch on your towed vehicle, and then it'll go over to the safety chain loop on your hitch. With all of your connections made, you now just need to place your vehicle into tow mode and you're ready to hit the road.And that completes our installation of Demco's Air Force One supplemental braking system on our 2019 Jeep Grand Cherokee.


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