The convection portion of the unit works but microwave will not turn on because it says door open. I unpluged and plugged in, still same error. I let it sit for two years and used small microwave instead but still used the convection. then tried the microwave for fun and it worked .. for a day or so but now get the door not closed message. So from what I read it could be a fuse? could be the latches, could be something in harness. where should I start? I was going to put new latches in first but thought I would check options