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Microwave light bulb not working

If your microwave light is not working, the light bulb itself is the most likely cause, especially if the microwave operates normally and the microwave light is burned out. Replace the bulb or LED light before replacing related parts, and enter your model number to find the exact microwave light replacement for your appliance. If your model uses a halogen lamp, test it with a multimeter for continuity or install it in an identical socket. Next, inspect the light socket and wire harness, then test the main control board to verify that it sends the correct voltage to the light socket. A defective door switch, including the primary, secondary, or interlock switch, can also prevent the cavity light from turning on when the door opens. Test each switch for continuity and replace any failed switch. A control board or micro switch can cause the same symptom, but these are less common. Any repair that requires opening the outer cabinet must be handled carefully because the high-voltage capacitor can store a lethal charge even after the microwave is unplugged. Proper capacitor discharge is required before interior work, so use a qualified technician if you are not familiar with that procedure.

01 - Microwave Light Bulb

The light bulb itself might be burned out. Replace the light bulb before replacing any of the parts associated with the light bulb
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Top Solution

02 - Microwave Halogen Lamp

To determine if a halogen lamp has failed, you can use a multimeter to test it for electrical continuity, or install the lamp into an identical socket to test it.
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Top Solution

03 - Microwave Main Control Board

Before replacing the control, check the light bulbs, sockets, and wiring. If these parts seem to be working properly, test the control board with a multimeter to determine if it sending the correct voltage to the light bulb socket. If the control board is not sending enough voltage to the light bulb socket, replace the control board.
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Highly Likely

04 - Microwave Door Switch

A defective door switch may not signal the control board that the door is open or closed which may prevent the microwave light from turning on or prevent the button that controls the light from functioning. 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.
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Highly Likely

05 - Microwave Control Board

A microwave light bulb not working could be caused by a defective control board, although this is rarely the case. Before replacing the control board, check the light bulbs, sockets, and wiring. If these parts seem to be working properly, test the control board with a multimeter to determine if it sending the correct voltage to the light bulb socket. If the control board is not sending enough voltage to the light bulb socket, replace the control board.
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Common

06 - Microwave Micro Switch

A defective micro switch may not signal the control board that the door is open or closed which may prevent the microwave light from turning on or prevent the button that controls the light from functioning. To determine if any of the micro switches are defective, use a multimeter to test each of the switches for continuity. If any of the micro switches do not have continuity, the switch or switches should be replaced.
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Common

07 - Microwave Power Supply Board

A microwave light bulb not working could be caused by a defective power supply board, although this is rarely the case. Before replacing the board, check the light bulbs, sockets, and wiring. If these parts seem to be working properly, test the power supply board with a multimeter to determine if it sending the correct voltage to the light bulb socket. If the board is not sending enough voltage to the light bulb socket, replace the board.
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Less Common

Frequently Asked Questions

Why is my microwave light bulb not working?
How do I test or replace a microwave light bulb or halogen lamp?
Can a microwave door switch cause the light bulb not to work?
Could the control board be causing my microwave light to stay off?
How do I find the correct microwave light bulb replacement part?

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