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Stuck Fan Relay or Overheat Protection Mode
Microwave fan runs continuously even when not cooking
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Safety Warning
This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.
If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.
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Possible Causes
Stuck fan relay on control board, Overheated cavity or magnetron, Faulty temperature sensor, Control board logic fault
How to Fix / Troubleshooting
Safety: Unplug the microwave before internal inspection.
User-level checks:
- Allow the microwave to cool for 30–60 minutes; some models run the fan to cool internal parts.
- If the fan continues to run indefinitely, unplug the unit.
Technical steps:
- Inspect the control board fan relay for signs of sticking or burning.
- Test the cavity and magnetron thermal sensors for proper resistance.
- Replace the control board if the relay is stuck closed or logic is faulty.
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Repair Difficulty
Hard
4/5
Required Part
Main Control Board
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