On ours (not a Jayco) the 7-pin green wire is for "Running lights and licence plate" (could your ground be lost at the licence plate?)
The "running lights" are what I call "clearance lights." I don't know on ours if they are split into groups by location, what a nightmare
:(. I don't know what the OP means by "parking lights" either.
As a quick fix, if you want to go camping, can you get at the ground for one of the red lights at the back and run a wire down the back ladder to the frame, taping it to the ladder so it stays there? (Assuming that one working would light them all up as suggested above)