We have a KitchenAid KEMS307D KEMS377D Microwave Broiler Oven combination wall unit. The lower oven door latch melted during a self-cleaning cycle. We have had this double oven unit for eight years and it first happened this past Spring. We had it replaced. The repair man stated the latch unit was a design defect because the housing which is plastic can not withstand the high temperature and melts. Well, yesterday, I used the self-cleaning feature for the first time since last Spring and the replacement unit apparently melted and the door is locked. Oh, I can unlock it with a screwdriver or other slender object. My question: other than self-cleaning (which I will now do the old fashion way), is it necessary to replace that latch part? If so, what is the part number? I can't seem to find a manual that list parts or repair functions. I don't need the owners cooking/trouble shooting manual. I have those.