Symptoms
- Fan doesn't respond when the vent button is pressed
- Microwave cooking function may still work normally
- Light on the unit may still work fine
- Grease buildup visible on the filter
Likely causes
- CommonGrease-clogged filter or fan bladesHeavy buildup can bind the fan motor so it won't spin.
- CommonFaulty fan switchThe switch controlling the vent fan can wear out independently of the cooking controls.
- PossibleTripped breaker or blown fuse for that circuitSome homes have a dedicated circuit for the range microwave.
- PossibleFailed fan motorLike any motor, it can burn out over years, especially without regular cleaning.
What to do
- Check that the microwave itself has power by testing the cooking function or light.
- Remove the grease filter (usually slides out from the bottom) and wash it in hot soapy water.
- Look at the fan blades through the filter opening for visible grease buildup and clean what you can safely reach.
- Try the fan switch again after cleaning.
- Check your home's breaker panel for a tripped breaker feeding the microwave/range hood circuit.
- If the fan still won't run after cleaning and confirming power, the switch or motor likely needs professional replacement.
Tools and parts
- Dish soap
- Screwdriver
Microwave vent fan motorSearch: “over the range microwave vent fan motor replacement”
Microwave grease filterSearch: “microwave grease filter replacement”
When to call a pro
If cleaning doesn't restore the fan, an appliance technician can test the fan switch and motor.
Safety
Generally low risk
Generally low risk for a careful person. Stop if anything looks different from what this guide describes.