Microwave-not-heating-door-switch, if your microwave oven doesn’t heat, you may have a problem with a door switch. the door switches, often referred to as interlock switches, provide power to the various components in the microwave when the door is in a closed position, and interrupt power when the door is open.. Sears kenmore 721.80044700 microwave will not heat or rotate the turntable -- how to i had a client come to me and they have a 721.80044700 microwave and it ..., if your microwave is not heating, the first place to look is the door switch. just in case the door isn’t latching and therefore the cycle isn’t starting. you can also check out the voltage diode. but if you determine that it’s the magnetron, you might as well replace your microwave.