Exactly, why I typed "power supply". It would read about 12.6 volts DC with no load on my DVM. But would also read about 5.0 volts AC. The the older modules worked just fine with it, and the newer did absolutely nothing, dumb luck. Shame on me for not realizing of it sooner.
Anyway. To bring this back to the original subject of the thread. The Ford module can function with as few as 5 wires; power, ground, lock, unlock, and program. I looked up a 2004 Journey system. It has 8 wires, those 5 plus: a second power wire, parking lights, and porch light. Not sure what the 2nd power wire is, looks like they both go to the chassis fuse block. Winnebago describes one as coach, and one as chassis power. The Ford module has an output for the parking lights, and one for the interior lights (although I think it's just a signal, you'd need a timer/latching relay to have the exact same function).
So, a quick trip to the junkyard for a module, a few minutes to hook up a some wires, and less than $10 on ebay for a fresh Ford fob (or maybe free in your junk drawer - like me), and you'd have replaced your SCS/Frigette system. Add 8 more wires and you could have a keypad.
I didn't see in the Journey diagram where the bay locks link to the keyless, but the Ford system could easily be set up to unlock the main door on the first click, and the bay locks on the second.
(I'm also going to use a "relay memory module". It's from a Ford van. It will lock the door 2 seconds after it's closed if the lock command was issued when the door was open. I'm using a set of jamb contacts like Winnebago uses on the side door, so it won't lock when it's open. The memory feature insures the door will lock. I think diesels with the front door have continuous wires to them and wouldn't require this function.)