I finally got around to posting on this thread now that I have the device installed and checked out.
I decided on a SMI Air Force One unit. It was the least problematic to install and the control box fit under the hood on top of my secondary fuse/breaker box on the driver side of the engine compartment.
The system uses air from the motorhome's air system to pressurize a tank in the control box. The brakes on the car are only activated when the coach brakes are applied by the brake pedal and not when the engine/exhaust brake is on. The usual means to apply the car brakes is a sensor on the coach brake light. When the brake lights come on the car brakes come on. The downside of this is that it applies the brakes at full force each time the rv brake lights come on. There are some units out there that also have a pendulum switch that senses inertial changes and it links to the rv brake lights and unless the rv/car are slowing down and the brake lights are on the brakes will not come on. This is a SMI Stay and Play unit.
The Air Force One is a proportional braking system meaning that the amount of force on the car brake pedal is proportional to the amount of air pressure used on the coach's air brakes. This is an ideal system when you have a heavy motor home (mine is 41,000# loaded for a long trip) and also a heavy car (5000#).
The basic components of the system include:
Control Box, brake pedal pressure adjustable valve with cable mounted to the firewall, air lines from the front grill to the control box and from the brake pedal valve to the control box, break away switch wiring to various places, power and ground wires to the control box, radio transmitter mounted on inside of windshield (communicates car brake pedal function to me in the motorhome), cutting into the car brake vacuum lines and intalling T's and back-check valves, etc. Very time consuming to find the best route to run wires without tearing up other stuff and finding pathways through the fireall in several places.
I have pulled a car almost this heavy with the other SMI system for 8 years and a bit over 50,000 miles with no incidents. So I have faith in the company and their product. In fact the older product was removed from my previous car (not a Jeep) and given to my cousin who has installed it in his Highlander and is very happy with it.
The worst part of the installation was actually trying to attach all the various connectors to the front of the car. These include: light harness cable, break-away switch, air valve from the coach and of course the base plate. I had a friend who is much better at fabrication (and he has the tools) to help make some brackets to attach to the front bumper. The grill is all plastic and does not lend it self to attaching anything to it. I did end up attaching the lighting harness connector to the grillwork with large fender washer. It looks good but is a bit delicate when removing the harness from the connector.
The next worse thing was the actual tail light lighting. Normally one either uses a diode(s) and ties into the car's wiring for brake, lights and turn signals but the dealer, who I had do the baseplate install, said JCA did not want diodes in the wiring. The next option was to intall an independent light bulb with duel filaments or a LED bulb in the actual tail light housing. Again, the dealer said No they would not drill a hole in a $450 housing. So I did it. I let them run the wires down the frame since it was already up on a hoist and I don't have the means to get the car that high up. I opted for the LED bulb because it is a lot smaller in diameter than the glass bulb. I used black RTV to hold the bulb in place and so far so good. No damage to the LEDs around the tail light (which is what the dealer was afraid would happen) and the LED is bright enough.
I also added the Tail Light Solutions rear fog light assemblies were the rear reflectors were. These are tied into my lights so them come on when the other light do. You can't have enough lights on your tail when you are towing a car behind a motorhome. People seem to not see the car or think it is just tailgating the RV. I want them to SEE the brake lights come on when I am slowing down. I have had s few close calls with folks not paying attention so the more lights to better in my book.
I have a few photos of the finished product only. The other installs were time consuming and done over a period of 3 months. I would be happy to post photos if anybody wants them.
The other thing I did at the same time was to install my HAM radio into the car. One reason this all took so long was trying to route wires, cable, antenna coax etc. through the car. Not and easy task and I am a very careful person especially with a new car.
Everything is now done and it all works to my satisfaction. Not without having to remove the front lower grill assembly about 10 times and tweaking the fit of the grill around the various parts that must be there to tow the car. I'm glad it is done.