Make sure that you indeed have the house "Aux" battery disconnect turned on. Then I would recommend you clean ground connections on the frame and both cable connections on battery bank. I do not think Winnebago has a thermal breaker in the system; only fuses and resettable circuit breakers. Good luck and keep us posted.
Mike, RVIA & RVSA Certified Master RV Technician
Amy, Dr. Assistant - Roxie & Mei Ling, four legs each
2000 Gulf Stream Scenic Cruiser 450 hp & 1330# torque
06 Saturn Vue, 06 Chevy Z71 4x4 & 2014 Corvette Z51 M7