I am posting this message to help all those who may one day experience the same problem I just resolved.
I have an A/C circuit that has 3 outlets then a GFCI outlet followed by four more outlets and a switch controlling two wall sconce lights. The problem I had was none the outlets nor light sconces worked. I put a test plug in the outlets one by one. The indicators showed normal connection. As soon as I applied a load to the circuit (plugging in a device or turning on one of the lights) the test plug indicated REVERSED HOT AND GROUND. Looked like a bad GCFI Outlet or a compromised neutral somewhere.
I replaced the GFCI outlet and the condition persisted. I pulled the lights and switched and checked the connections. Problem persisted. Then I pulled the outlets one by one. I found a neutral wire came loose on, of course, the last outlet on the circuit.
Now the reason I am posting this. These outlets are not the type that had screws that the wires attach to. Rather they use pinch blades that cut thru the wire insulator to make contact. Talking to my RV Technician he says many RV's use these outlets now. I know there are many new type outlets used in the housing industry now and these blade outlets are among those. They may work very well in a home, but add the bouncing down the highway that an RV does, it is no wonder these wires come loose.
I hope this helps someone save some time down the road.
My next project now is replace these outlets with the old fashioned screw type outlets.
John, Joyce and Zoie (our 17# Guard Dog)
2018 Ford F-450 KR / 2019 Mobile Suites 40KSSB4
Fulltiming since 2008 and loving it