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HomeRepair HelpLG Microwave RepairLG Microwave exhaust fan not working Repair
LG Microwave exhaust fan not working
If your LG over-the-range microwave exhaust fan is not working, start with the door switch, which must signal the control board that the door is closed before the fan control can operate. Test each door switch for continuity and replace any switch that fails. Next, check the exhaust fan motor. The fan blades should turn freely by hand; if they do not, replace the motor. If they turn freely, test the motor for incoming power and continuity. A defective thermostat is another likely cause because it monitors air temperature and activates the fan when needed. Test it for continuity and replace it if the circuit is open. A clogged or damaged grille can also restrict airflow, so clear obstructions and replace the grille if necessary. If the motor is not receiving power, the LG control module or wiring may be faulty, although the module is less common. Finally, test the microwave micro switch, which can cause the same door-signal problem as a door switch. Enter your model number to find the exact replacement part for your LG microwave. If any diagnosis requires opening the outer cabinet, unplug the microwave first and note that its high-voltage capacitor can store a lethal charge even when unplugged. Proper capacitor discharge is required, and a qualified technician should handle this work if you are unfamiliar with the procedure.
01 - LG Microwave Door Switch
A defective door switch may not signal the control board that the door is closed, which can prevent the button that controls the exhaust fan 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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02 - LG Microwave Exhaust Fan Motor
To determine if the fan motor is defective, remove the fan motor from the microwave and try turning the fan blades by hand. If the blades do not turn freely, replace the fan motor. If the fan blades do turn freely, use a multimeter to test the motor for incoming power and for continuity. If the motor has power but won’t run, replace it. If the motor does not have continuity, replace it.
Top Solution
03 - LG Microwave Thermostat
The thermostat monitors the air temperature and turns on the fan when necessary. If the thermostat is defective, it won’t turn on the exhaust fan at all. Use a multimeter to test the thermostat for continuity. If the thermostat does not have continuity, replace it.
Top Solution
04 - LG Microwave Grille
A damaged or clogged grille can prevent the air from being properly exhausted when the exhaust fan is turned on. Confirm the grille is free of obstruction and, if the grille is visibly damaged, replace the component with a new one.
Highly Likely
05 - LG Microwave Control Module
If the microwave exhaust fan is not working, the control module might be defective. However, this is not usually the case. Before replacing the control module, first check the exhaust fan motor and wiring. If the exhaust fan motor is not getting power, the control module might be at fault and require replacement.
Common
06 - LG Microwave Micro Switch
A defective micro switch may not signal the control board that the door is closed, which can prevent the button that controls the exhaust fan 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 switches do not have continuity, the switch or switches should be replaced.
Common
Frequently Asked Questions
Why is my LG over-the-range microwave exhaust fan not working?
How do I test an LG microwave exhaust fan motor?
How do I test the door switch or thermostat when my microwave fan is not working?
Should I replace the LG microwave control module if the exhaust fan does not run?
How do I find the correct LG microwave exhaust fan motor or door switch?
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