Micro Switch with Line Fuse

To determine which switch was bad, I removed all three switches from microwave. I used a D-cell battery taping two pieces of wire to the POS and NEG ends. Tape the POS end of wire to a flashlight bulb's bottom tip. Tape or twist the NEG end to the bottom of the switch. Connect another piece of wire to the top of switch and touch the side of the flashlight bulb with the other end of the wire; the bulb should come on. Depress the red button on the switch and the light should go out. The switch is good if this occurs. If light does not come on or the bulb does not got out once the red button is depressed, the switch is bad. Now you have determined which switch to order for replacement.