Did you try calling Newmar? We've had our Winnebago for 12 + years, and any time I've called them with a troubleshooting question, they were quick to help, with suggestions, downloadable pdf files for wiring, plumbing, structural, etc, or you can buy the printed/bound maintenance diagrams. Worth a call?
Bill, (aka Capt.Bill)
2002 Horizon 36LD, Cat 330
RVing since 1987
First State