The isolator separates the coach batteries from the starting battery. It connects them in parallel only when the engine is running to prevent running down the starting battery. But, nearly all motohomes have the "emergency start" function which also manually parallels all the batteries together in case you drained the starting battery.
The fact the generator faulted out at the same time really makes me suspect a bad isolator. It would be an awfully big coincidence for both the generator and the Ford PCM to stop working at the same time. And... if the isolator were working, it would protect the Ford wiring from any voltage spike caused by a freak generator failure.
I've never once seen a Ford PCM fail causing a no-crank condition. When they go bad, they typically cause a crank but no-start condition. I have seen numerous isolator failures.
I can also confirm that is a non-PATS key. All Ford PATS keys use the larger housing (however, aftermarket non-PATS keys can also use the larger housing).
