[CaptainGizmo]

With all that said, another reason to disengage whatever you are doing as I was already wondering its purpose.

Barry,

That's really bad what happened.  I have a lot of questions, but hopefully, you'll find out what the cause was.  But, I some points that could use some clarification:

1. What year is your coach?  As you've read above, not all are created equal. However, Newell started installing these auxiliary air tanks that are used to supply the "trailer" with air.

2. You say "another reason to disengage"...and I'm confused at what you mean, so forgive me if this is pointing out the obvious. Before towing with any "trailer" or "toad" that is connected to that rear air chuck, the "Trailer Brake" must be CHARGED...or ENGAGED (not disengaged).  This seems counter-intuitive, for sure, since that valve is NOT a parking brake for the trailer. Rather, it is a valve that puts air into that auxiliary air tank as well as, apparently on our coach, enables the brake light circuit on the 7-pin.

3. With that system "charged", pushing the coach's air brakes causes pressure to be sent to the AF1 via that rear air chuck. Without any air in that system, the TOAD'S brakes will not be applied in this normal manner.

4. Also, as a friend just discovered, if at any time, that "emergency pin" is pulled on the AF1, the AF1 will engage the brakes! This means when some low-life decides to "make your day miserable" and pulls that little pin out...you've got problems! Luckily, for my friend, his Yukon was just sitting in a parking lot and...after a certain time...the AF1 becomes inactive so he was able to drive his Yukon just fine and order more pins. Had he been parked somewhere, with that AF1 active and charged up with air, things would have turned ugly. And, quite frankly, what happened to YOUR Cherokee would be exactly what would happen if some yahoo pulled your pin and you drove off.

5. Only other thing I can think of that will "pull" on your brakes is an issue with your setup. A lot of people do NOT take into consideration that they have MOVEABLE pedals (brake and accelerator)!!! Soooooo, when the air solenoid and cable are installed and adjusted for slack with the pedals all the way DOWN TO THE FIREWALL, and at a later time, the driver adjusts the pedals TOWARDS THE DRIVER...then this will cause tension in the cable which is attached to the brake pedal...and BOOM...you've got your TOAD's brakes to be applied!!
On my Raptor, I had the installer set the cable tension with pedals ALL THE WAY UP (towards driver). This way, there is NO WAY for the pedals to be moved end up pulling tension. Instead, each time I get ready to tow, I use my memory preset which moves the pedals all the way up, which is where the proper tension is set. All other times, when the pedals are down, the AF1 won't pull enough cable to activate the brakes...so it's a failsafe; worse case is, if I forget, no brakes will be activated.

Hope this makes sense and helps.