I threw in the towel! The inline fuse was not blown and the inline Temp Cutout has continuity. An envelop inside contained a very good schematic and trouble shooting instructions. The problem is most likely in the door interlock switches (the most used components), but they are not easily replaced from the front panel access. Removing the unit to get better access is not easy due to the weight and very tight access to the mounting screws.
Heeding the advise of most of the Forum,and upcoming travel plans, I located a better replacement at Home Depot (on sale) and a nearby Newmar dealer will replace it for me next week.