From your description it sounds like your 12V system is down, are you plugged in and if the microwave is face lighted you have 110V power. it may be the 12v side of your converter has gone. To get you buy if it is the controller you can use a 12V battery charger plugged into you 110V outside outlet and connected to the coach batteries to give you the 12V power you need.
Jake my sidekick (yellow Lab)
2017 RAM 2500 CC 4X4 Cummins Diesel
2016 Flagstaff 26 FKWS
AF&AM of Idaho