How to Fix / Troubleshooting

Safety: Unplug the microwave or switch off the circuit breaker before servicing the fan.

Check fan settings: Verify that the fan is not set to Auto mode that only runs with certain conditions. Try all speed settings.
Inspect filters: Remove and clean grease filters. Excessive grease can restrict airflow and strain the fan.
Access fan motor: Remove the top grille and any necessary panels to access the vent fan. Check for obstructions or grease buildup on the blades.
Test motor: If the motor hums but does not spin, or does not run at all, it may be seized or burned out and should be replaced.

If only one speed works, the control board or fan speed switch/relay may be faulty and require replacement.

Over-the-range Kenmore microwave vent fan does not run or runs only on one speed when using the hood function.

Possible Causes