GE Microwave / Hood has internal circulation fan on when door is open

Aug 5, 2002
Silicon Valley
So this started a day or so ago. When I open the door after I microwave something the circulation fan turns on despite the magnetron is no longer nuking the food. I tested with a bowl of stuff in there that would have sizzle if the microwave is on and the door slightly open (me behind some metal plate to protect myself), and the food didn't sizzle, so the magnetron is not on when this happen.

I googled and it seems like the common consensus is the door interlock switch is worn or stuck, then someone also said it was a bad thermostat / thermal overrun or protection switch.

At about 8 years this thing seems to be doing ok, the only concern if I were to replace the whole thing instead of repairing these switches is: will the tile in the back align if I replace it, or will something stick out or cannot fit back in? I would rather repair these switches to save the trouble if the back splash didn't cover all the way up or other nonsense, or I have to cut different holes in the back to fit the vent, mounting, etc.

Your thought?
I have a similar Whirlpool. I hate the blasted thing. When it quits, I’m putting in a stand alone range hood and going to a countertop microwave.
FYI: It was here when we bought the house.
I just went through this with mine. Look at the youtube videos of replacing parts, it is fairly easy to do if you are mechanically inclined in the least. And no, there is no guarantee the new one will match the tile of the old one, ask me how I know!
I just replaced the original GE microwave that came in my parent's late90's-2000ish house. It still worked but they wanted a new one. I bought another GE and it bolted right up using the existing bracket and holes in the upper cabinet. I had to trim off 1/4" or so from the end of the wall bracket with some tin snips but it was plug and play otherwise.
My Kenmore did the same thing years ago. I replaced a bad micro switch to fix the problem and it was an easy task to do.