Most RV lights are 12V and hence have nothing to do with AC or GFIs so it sounds like 2 different problems. My GFIs have a green light when they are working - so does your GFI have AC power but no downstream power?
If a GFI doesn't reset, is OK and there is no miswiring then it's neither a short or open - instead it's a ground fault - ie a small amount of current leaking to ground.
You need to post the rig/year and model number of all related equipment. Good luck on getting any accurate wiring diagram as mfgs are know to make numerous production changes.
And on top of that:
i changed all outlets inside and out of coach and fuse box and fuses.have a volt meter,but never used one
this suggests you should hire help considering you rewired the plugs.
