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Monitor your supplemental braking system from the cab of your RV as you're flat towing. Transmitter installs in your towed car and sends signals to the plug-in monitor in the RV to let you know the system is working properly.
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Videos are provided as a guide only. Refer to manufacturer installation instructions and specs for complete information.
Speaker 1: Today our 2019 new Marvin Town and Motor Home, you're gonna be taking a look at, I'm gonna show you how to install the SMI Coachlink 900 Wireless Transmitter and Receiver Braking Indicator Set. Part number SM99945.The main reason for a Coachlink is that it tells us our brakes are being applied in our towed vehicle. We have an indicator light mounted to the rear view mirror. That's the rear braking system. The problem is, in our rear camera, that little bitty light on that mirror is hard to see. This gives us the ability and peace of mind that we can look at this little screen right here and know that our brakes are being applied in the vehicle, because it's tied into the same wiring.As far as the installation goes, it's a very simple installation.
You can see on the RV side, 12 volt power. It just needs to be plugged in. This is a wireless system. The side that goes into the vehicle, it's got a, two wires. A red and a black wire that ties into your indicator light and your read switch on your Air Force One braking system.Your Coach is where the camera stays on in the back all the time.
It's great. You can see your indicator light a little bit. But what happens when we turn on our blinker The screen goes off. And it turns on our camera for our blinker side. So now, we don't know if our indicator light on our rear view mirror is coming on.
We do if we have a Coachlink.So now we'll go ahead and we're gonna make our connections with our Coachlink. And this is what the box for the inside looks like, and this is gonna be mounted somewhere under the dash. We're gonna have a red wire and a white wire coming off it. Strip both of these back here real quick. And I have some extra white wire I'm gonna use for a ground.
I'm gonna connect my red wire with my red wire coming from my indicator light. Red wire off the Coachlink to the red wire off the indicator light.White wire with my black wire off my indicator light. My white wire from my ground I'm gonna connect to my blue wire for my read switch, and it's gonna go to the black wire for my indicator light. And my white wire coming off my Coachlink. Black wire to my red wire. And then my brown wire coming off of my read switch to my brown wire routed outside, which is gonna get connected to the orange and black wire coming off our breakaway switch. And then to the positive side of the battery.Next, we'll have some hook and loop. This, just get that pushed in place right around now. So we can bundle up all of our wires, and theirs is factory wiring right up here. Then if we run this right over the top along with our bundle, we can zip tie it right up to all of that. It'll stay nice and hidden. You can see right here, right behind this front wheel, there's a green light.This is telling you that it's on and it's connected to the vehicle side. What we'll do is we'll turn it on. You have an on and off switch here. This is for the buzzer for the audible alarm. Now when we apply the brake, we're gonna see three lights here. That's telling us that the brake pedal in our towed vehicle is being applied, or our braking system in our towed vehicle is applying the brake.You want to push on it. See three lights. We're gonna see the light here on the screen. It's our indicator light on our mirror. When I let off the brake pedal, those three lights will go off, and that light should go off. That's telling us our brake pedal was released. That'll do it for a look at installation on the SMI Coachlink 900 Wireless Transmitter and Receiver Braking Indicator Set, part number SM99945 on our 2019 nEw Marvin Town and Motor Home.
Demco Air Force One is the best system for motorhomes with air brakes! Our setup has been flawless the last 2 years. We just got a new Wrangler Sahara so I needed to uninstall and reinstall on the new Jeep; in doing so I upgraded to the Coachlink. The led strip that installs on the rear view mirror is adequate but hard to see with the back camera on a sunny day.
System works well, but the wiring directions are not correct when you install this after you install the Air Force One with the LED light. It took me about an our of trouble shooting to get the wiring correct, Demco needs to update wiring diagram
Online videos contradict written wiring instructions for this product. Recommend reviewing your website installation videos.
Definitely needed in bright sunlight. Easy to set up and install. Worked well in a Jeep Liberty and 40 ft Tiffin.
Dana’s
10/27/2025
Still working well and worth the money.
Excellent product offering the ability to easily monitor the tow vehicle brake activation on a monitor right in front of you is a welcome change. Many thanks to Jim D for his idea of cutting off the LED brake indicator plug and butt connecting it to the transmitter. I took Jim's idea one step further and went to my local electronics store and purchased the same kind of plug and wired it to the SMI Transmitter. This way I can still use the LED indicator as a backup if ever needed by simply unplugging the transmitter and plugging it back into the LED. With the new plug I purchased the SMI Red Wire was connected to my new plug's Brown wire and the SMI White wire was connected to my new plugs Red wire as shown in the attached picture. Plugged it up and it worked great. So much simpler than having to splice into the SMI Duo wiring harness.
Chuck R.
1/31/2018
Thanks for the note. In answer to your question, Yes I still like the SMI dash monitor and it is still working great. Makes it a lot safer seeing right in front of you if your brakes are activated. Thanks
Excellent addition to the Demco braking system! Should be a standard component.
It allows verification of towed vehicle braking from the coach without distraction from forward vision.
Very pleased with ease of installation and use.
Thanks etrailer for another quality product!
Dean
1/21/2025
The Demco wireless braking monitor has provided trouble free visual andor audible indication of brake application to the towed vehicle. The monitor can be placed in line of sight eliminating distractions while driving. thanks to e trailer for providing a complete line of quality towing products.
This item makes it much easier to monitor toad braking than trying to find a small red light with the rear view camera.
Using this on my 2025 Maverick installation was straight forward have not used it yet.
Just installed the SMI CoachLink 900 Wireless Transmitter and Receiver Braking Indicator Set in my Honda Fit and Navion Motorhome. Less than 10 minute install to my existing Stay and Play Duo brake system. It just can't get any easier to have a better indication of how my braking system is performing for me from the drivers seat in the motorhome. I added an indicator light in my Honda to let me know that the Duo brake system is active when I turn on my GForce Controller.
Installed this Demco wireless on my 2016 Jeep and when towing it with my RV it works perfectly.
This is so much better than trying to see the brake indicator from the RV camera
I installed this instead of the included Air Force One LED light indicator. The installation of this combined with the wiring of the reed switch on the AirForce One braking system caused some wasted time. The brake cylinder on the AF1 only had 2 wires whereas the instruction manual showed wiring for three wires. Recommend you follow the pdf installation wiring diagram. Have not tried this yet, just finished install.
Great product, has worked perfect since I installed about a year ago. Having the brake indicator on the dash instead of on the toad windshield is a major improvement in usability and safety. Having a wireless solution is a huge bonus, makes installation very easy since you don't have to run bumper-to-bumper wires (which on most coaches and modern cars can be a real PITA). Also very easy to connect the Demco Air Force One brake indicator switch to the Demco wireless transmitter.
It arrived prior to my deadline as promised. There were no instructions in the Coachlink box but I found them on the web easily enough. I have made three purchases from etrailer and have leaned on them with questions and for technical support. Messages are returned very quickly and they always are helpful. Prices are competitive. I try to order from etrailer whenever possible as they are very easy to work with and are always available with help if needed. Great company and people.
Steve F.
3/23/2018
Its been a year since my review and I havent needed any parts from eerailer. My opinion has not changed, they are they are one of the top places I go to for prices and help.
Great product! I finally broke down and installed this Demco product after numerous efforts to get reliable feedback on braking status from the Air Force One in my toad ... seeing LEDs from the motorhome rear camera and running wires through the wiring connect to a dash light were all sub-optimum. Installing the Demco system was easy, the instructions include wiring diagrams for a number of different braking systems. Once the toad wiring was complete I located the control box where I could see it while driving, plugged it in ... and it worked perfectly! Great peace of mind, I use it as part of my pre-departure check list and glance down to get a confirmation most times I use the brakes.
I am very happy with the CoachLink 900. Easy to hook up and use.
Curt
12/9/2018
Its been working just fine. Still happy with it.
Easy installation. Simply replaced the LED brake indicator previously installed on the back of rearview mirror with the wireless transmitter supplied with this kit. Transmitter was mounted (using hook and loop tape), directly underneath the SMI G-Force Controller, which is mounted on the tow-kick panel and B-Pillar (besides the driver's seat). Although it appears this location might be in the way of the hood release, it isn't. There is still plenty of room for the hood release to operate on the 2014 Honda CR-V....other models may not have room, but the 2014 Honda CR-V has room. The end is cut off the LED brake indicator and butt-connected to the end of the transmitter and plugged in. The wires were removed from the tie that secured them to the dash (just behind the steering wheel adjustment lock lever) and excess wire was tucked under the carpet, easily accessible if transmitter should need moving later. Receiver activated as expected.
We purchased the Stay N Play brake system with the wireless transmitter, and wish we had done it years ago, instead of messing with the Brake Buddy that we had before. It is so easy now to get our Explorer ready to tow behind our RV, and we like the 'instant' breaking that the Stay N Play affords instead of dealing with the 'lag' that we had in our Brake Buddy. We would definitely recommend this excellent product.
The Demco Wireless Coach link arrived quickly like always from etrailer.
Everything in the etrailer pictures are exactly what you will receive. Hooking it up and setting it up could not be easier. I installed it in a 2014 Ford Edge. Only two wires to hook up. White goes to ground and the red wire was sliced into the cold side of the brake pedal switch. It was a purple and white wire. Found it by tapping on the brake pedal with a meter on each wire. Tuck everything away in the Edge and tested the unit. It worked perfectly as expected. I did not actually test it behind the motorhome as it was not available. If I run into any issue being about 50' away, I will update the review. So far, it's great!
The LED indicator for the back of the rear view mirror in the tow car is not always visible, sunlight, glare,etc. This unit makes monitoring the brake system easily visible.
I installed a demco air force 1 on my nautilus and purchase this monitor to replace the dumb lights that stick to the mirror of the toad. The wiring diagram for the coachlink was inconsistent with the wiring on the demco. Stupidly rather than call demco i followed the coachlink wiring. The result was it did not work. Called coachlink. They Pete great and aware of the issue. They replaced the sensor on the actuator no charge. Turns out that the coachlink also fried. I am onnthe road so i ordered a replacement which etrailer got to us. The service eas great just annoyed i had to pay another xxx$ for the second unit
Awesome tool for peace of mind that the braking system is working properly when towing. It was very difficult to see the provided light through the rear view camera and now I know immediately when the towed vehicle brakes are applied. Easy installation I did it myself.
This wireless brake lighting monitor works perfectly with my SMI Duo brake assist system. No constantly looking at rear camera on my motorhome. etrailer videos so helpful with entire series of installs on my Wrangler for flat towing.... Tow lights, brake relay, towed vehicle battery charger, SMI Duo system, and this monitor.
The wireless break indicator unit works well although it is difficult to see the power on light. Installation was a little “dicey” given the small gauge of the wiring but it went pretty smoothly.
I am using this kit with my Demco automatic braking system that I installed on my Jeep. I get a clear indication that the braking system is activating when towing the Jeep with my motorhome.
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Nick S.
9/8/2025
Thank you for that feedback I will definitely get our team to look at that. Were you able to get it installed alright?