I realize you have already said there are no bad wire connections, but what you're describing sounds like an open circuit somewhere. Check all of the wire connections, and the wires themselves, very carefully.
I hesitate to even bring this up, but I assume you checked all fuses and circuit breakers?
curmudgeon: noun; a crusty, ill-tempered, irascible, cantankerous old person . . . .
79 27' Holiday Rambler Statesman, 78 32' HR Imperial, 85 36' HR Imperial 5th Wheel