If your range hood light works but the fan will not run, hums without spinning, or stopped during cooking, the problem is usually limited to the fan side of the unit. Work from power and filters toward the switch and motor.
These steps apply to under-cabinet, wall-mount, and over-the-range microwave hood fans from most major brands.
Does this affect you?
A dead range hood fan usually comes from one of three areas: power is not reaching the motor, grease has jammed the blades or bearings, or the fan switch or motor has failed. Weak airflow can also come from blocked ducting or an overdue charcoal filter.
Check power and the fan switch
- Check the breaker feeding the range hood or microwave hood.
- If the hood light works but the fan does not, power is reaching the unit and the issue is likely fan-specific.
- Try every fan speed. Some speeds working while others fail points toward switch contacts.
- On microwave-hood combos, make sure the microwave door is fully closed and latched.
Turn off the breaker before removing covers, touching wiring, or checking the switch. Let nearby burners and hood surfaces cool first. Use a stable stepladder, and keep grease filters clean because heavy grease buildup is a fire risk.
Clean the grease filters and fan blades
- Remove the metal mesh or baffle filters from the underside of the hood.
- Wash them in hot soapy water or a dishwasher cycle if the manual allows it.
- With power off, inspect the fan housing with a flashlight.
- Gently nudge the fan blades by hand to see whether they move freely.
- Wipe heavy grease from the blades with degreaser on a cloth, taking care not to bend them.
- Reinstall filters, restore power, and test all speeds.
Check the fan switch or motor
If the blades are clean and spin freely but the fan still fails, the switch or motor is next.
- A motor that hums but does not turn can have a seized bearing or failed motor capacitor.
- A fan that does nothing on every speed while the light works often points to the fan switch.
- Testing the switch or motor requires a multimeter and access behind the control panel.
- If you are not comfortable with wiring, stop and call a technician.
For ducted hoods, weak airflow can come from a blocked or crushed duct. For ductless hoods, replace the charcoal filter every 6 to 12 months depending on cooking use.
If the hood is part of a microwave and both the microwave cooking function and fan are acting up, a door switch can be involved. If the breaker, filters, blades, and obvious airflow path are fine, have the switch and motor tested directly.
Sources
- GE Appliances – Range Hood Fan Not Working (2025)
- Broan-NuTone – Exhaust Fan Troubleshooting (2025)
- Whirlpool – Over-the-Range Microwave Vent Fan Not Working (2024)