This Is A Small Microswitch Used In The Microwave's Door Interlock System Or Control Mechanism. It Detects Whether The Door Is Properly Closed And Signals The Unit To Allow Or Prevent Operation For Safety. Replace This Switch If The Microwave Does Not Start When The Door Is Closed, Runs With The Door Open, Blows A Fuse Repeatedly, Or Fails To Respond When Buttons Are Pressed.