Quick Answer
Start with the hood lights. If both the lights and fan are dead, check the power supply. If the lights work but the fan does not, the fan control or blower is more likely at fault.
A fan that hums without moving air may have a stuck blower wheel, a failed motor, or a start capacitor on models that use one. Switch it off rather than trying it again.
Most Likely Causes
Power supply problem
When the lights and fan are both dead, an accessible plug or tripped breaker is the first thing to check. If the breaker trips again, leave it off.
Fan switch or electronic control failure
If the lights work but no fan speed responds, the switch or control may not be operating the blower. First rule out a control lock or delayed-off setting if your model has one. Internal testing is technician work.
Blower wheel obstruction
The blower wheel moves air through the hood. Grease buildup or a loose part can obstruct it, sometimes causing a hum or scraping sound. Cleaning the removable filters is safe, but reaching into the blower housing is not.
Blower motor or start capacitor failure
A failing motor may hum, run intermittently, or stay silent. On models with a start capacitor, that part can also keep the motor from starting. Neither symptom identifies the failed part without testing.
Dirty filters or restricted exhaust
These usually cause weak airflow rather than a fan that will not start. Grease filters can clog, while a blocked duct or stuck outdoor flap can restrict a ducted hood. A recirculating hood may also have a charcoal filter that needs replacement.
Safe Checks to Do First
- Try each fan speed and check the lights. Use the owner's manual to clear a control lock or delayed-off setting, if fitted.
- Reset a tripped breaker once. If the hood has an accessible plug, check that it is seated without moving the hood or opening a panel.
- Turn the hood off and let it cool. Remove the grease filters as the manual directs. Clean them, let them dry fully, and reinstall them.
- If the hood recirculates air, check its removable charcoal filter. Replace it with the specified filter if the manual calls for it. Most charcoal filters are not washable.
- For a ducted hood with weak airflow, look at the outdoor vent flap only if it is visible from the ground. Do not climb or take ductwork apart.
What the Symptoms Usually Mean
Lights work, but the fan is silent
This most often points to the fan control or blower circuit, not the hood's main power supply.
Fan hums but does not spin
This usually points to a stalled blower wheel or a motor that cannot start. Leave it off to avoid overheating.
Fan runs, but airflow is weak
Dirty grease filters or a restricted exhaust are the first suspects. On a recirculating hood, check the charcoal filter too.
Fan stops after running
An overheating motor or restricted airflow may be responsible, especially if it starts again after cooling. A timed or automatic setting can also stop some models normally.
Breaker trips when the fan starts
This points to a possible motor or wiring fault. Leave the breaker off.
When to Stop DIY and Call a Technician
Stop if the fan hums without turning, repeatedly stops, trips the breaker again, or produces a burning smell. If the safe checks do not explain the problem, internal wiring, the control, blower, motor, and capacitor are technician work. Arrange a range hood repair visit.
