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Sharp Microwave turns on by itself

If your Sharp microwave turning on by itself may have a normal explanation or a failed control component. On most Sharp over-the-range microwaves, the vent fan automatically turns on during stovetop cooking when a thermostat senses excess heat, then shuts off after the microwave cools. If the microwave fan turns on by itself when the cooktop is not hot, check the touchpad first. If the touchpad responds correctly, a defective main control board is the most likely cause. A malfunctioning interlock switch can also cause the microwave to start unexpectedly, especially when the door moves. Inspect the switch holder behind the control panel for damage or misalignment, since it may prevent the door switches from engaging correctly. Less commonly, intermittent contact between circuits in the touchpad and control panel, or in the touchpad itself, can start the microwave without a command. Enter your model number to find the exact replacement part for your Sharp microwave. Any repair that requires removing the outer cabinet must be handled carefully because the high-voltage capacitor can store a lethal charge after the microwave is unplugged. It must be properly discharged before interior work, so use a qualified technician if you are not familiar with capacitor discharge procedures.

01 - Sharp Microwave Main Control Board

First, make sure that the touchpad is working properly. If the touchpad is working properly, the main control board is likely at fault. If the control board is defective, replace it.
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Top Solution

02 - Microwave cooling down during stovetop cooking

Most over-the-range microwaves have a vent fan thermostat that will turn the vent fan on automatically to keep the microwave from overheating. The fan will shut off after the microwave cools back down.
Highly Likely

03 - Sharp Microwave Interlock Switch

A microwave that turns on by itself can be caused by a malfunctioning interlock switch. You can use a multimeter to test the interlock switches to determine if they are functioning appropriately and replace if necessary.
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Common

04 - Sharp Microwave Switch 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, the switches may not be properly engaged which could cause the microwave to turn on by itself. 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.
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Common

05 - Sharp Microwave Touchpad and Control Panel

It’s possible that the touchpad and control panel button circuits are coming into contact with each other intermittently which could cause the microwave to turn on by itself. If this happens, the touchpad and control panel will need to be replaced.
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Less Common

06 - Sharp Microwave Touchpad

It’s possible that the touchpad button circuits are coming into contact with each other intermittently which could cause the microwave to turn on by itself. If this happens, the touchpad will need to be replaced.
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Less Common

Frequently Asked Questions

Why is my Sharp microwave turning on by itself?
Why does my Sharp microwave fan turn on by itself?
How do I test a Sharp microwave interlock switch or switch holder?
Could the Sharp microwave touchpad or control board be causing it to turn on by itself?
How do I find the correct Sharp microwave part for this repair?

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