Original post by: Adam Bollmeyer ,
Sorry, I checked the switches again. You're right, the top and bottom are NO, and the middle switch is NC. I was going off of memory when I wrote my original post, so I appreciate you bearing with me. I retested all the switches again, and they all "appeared" to be changing state when I closed the door, according to my multimeter. I ended up removing the switch assembly and tested each switch again. They all changed states again. I figured since I already had the switches removed, I would swap the two interlock switches. After I reassembled the microwave and tested it, it acted like the door wasn't shut (which would indicate the secondary switch was faulty, which was previously installed as the primary switch). Afterwards, I disassembled the microwave and removed the switch assembly again. The faulty switch would change states when I pressed the button, but I think the way I was testing it (the way I was holding it) was causing gravity to open the switch instead of the spring tab inside the contact. I don't know why I was getting the readings with it installed and testing with the door physically making the switches. Thanks for all the help Tim.