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KitchenAid Microwave Not Working

The part(s) or condition(s) listed below for the symptom Microwave not working are ordered from most likely to least likely to occur. Check or test each item, starting with the items at the top of the page.

Most Frequent Causes for Microwave not working

For the most accurate results, enter your model number.


Cause 1Line Fuse

If too much current passes through the microwave circuitry, the line fuse will blow. If the line fuse blows, the microwave won’t start. To determine if the line fuse is at fault, use a multimeter to test it for continuity. If the fuse does not have continuity, replace it. In addition, you should investigate and resolve the problem that caused the fuse to blow. If you don’t resolve the underlying issue, the new fuse will blow too. (Caution: The microwave oven can store thousands of volts of electricity in its high voltage capacitor, even after the microwave oven has been unplugged. Due to the potential for electric shock, it is extremely dangerous to replace the electronic components in a microwave. Only a licensed technician should replace the line fuse.)

Parts
Cause 2Micro Switch

Most microwaves have three or four door switches (micro switches). When the microwave door closes, the door switches actuate in sequence to ensure that the door is closed properly. If any of the door switches fail, the microwave will not start or heat. To determine if any of the door switches are defective, use a multimeter to test each of the switches for continuity. If any of the door switches do not have continuity, the switch or switches should be replaced.

Parts
Cause 3Door Switch

Most microwaves have three or four door switches. When the microwave door closes, the door switches actuate in sequence to ensure that the door is closed properly. If any of the door switches fail, the microwave will not start or heat. To determine if any of the door switches are defective, use a multimeter to test each of the switches for continuity. If any of the door switches do not have continuity, the switch or switches should be replaced.

Parts
Cause 4Main Control Board

The main control board might be defective. However, this is rarely the case. Control boards are often misdiagnosed—check all of the more commonly defective parts. If you have determined that all of the other components are working properly,replace the main control board. (Caution: The microwave oven can store thousands of volts of electricity in its high voltage capacitor, even after the microwave oven has been unplugged. Due to the potential for electric shock, it is extremely dangerous to replace the electronic components in a microwave. Only a licensed technician should replace the main control board.)

Parts
Cause 5Thermal Fuse

The thermal fuse cuts off power to the microwave if the microwave overheats. To determine if the thermal fuse has blown, use a multimeter to test it for continuity. If the fuse does not have continuity, replace it. The thermal fuse cannot be reset—if the fuse is blown, it must be replaced. (Caution: The microwave oven can store thousands of volts of electricity in its high voltage capacitor, even after the microwave oven has been unplugged. Due to the potential for electric shock, it is extremely dangerous to replace the electronic components in a microwave. Only a licensed technician should replace the thermal fuse.)

Parts
Cause 6Diode

Diode

Parts
Cause 7Thermoprotector

If the microwave overheats, the thermoprotector trips to cut off voltage to the microwave. To determine if the thermoprotector is at fault, use a multimeter to test it for continuity. If the thermoprotector does not have continuity, and it cannot be reset, replace it.

Parts
Cause 8Thermostat

If the microwave overheats, the thermostat trips to cut off voltage to the microwave. If the thermostat is shorted open, it may not allow voltage to reach the high voltage components. To determine if the thermostat is at fault, use a multimeter to test it for electrical continuity. If the thermostat does not have continuity, and it cannot be reset, replace it.

Parts
Cause 9Switch Holder

The microwave switch holder is the component that houses the door switches behind the control panel. If the switch holder is damaged or misaligned, one of more switches may not be actuated when the microwave door is closed, resulting in the microwave not working. You will need to uninstall the control panel and inspect the switch holder to confirm it is in good condition and secured properly. Replace the switch holder with a new one if necessary.

Parts
Cause 10High Limit Thermostat

High Limit Thermostat

Parts