AC Outdoor Fan Not Spinning? What It Means and What to Check
The outdoor unit is on — you can hear it hum, maybe feel it vibrate — but the big fan on top isn't turning. This is one of the most common summer failures, and the fix is usually a small part. But leaving it running is how a small part becomes a big one.
Safety first, every page: if you smell gas anywhere in the house, leave and call your gas company from outside.
First: turn it off
If the outdoor unit is humming and the fan isn't spinning, shut the system off at the thermostat now. The compressor is running with no fan to cool it. It will overheat and trip on its own eventually, but every minute counts against its lifespan.
Then check these
1. Is it really not spinning?
Watch for a full minute with the AC calling for cool. Some fans start slowly. If it never moves, or twitches and stops, it's not running.
2. Is it blocked?
Look through the top grille. A stick, a toy, a bird nest, a mat of leaves — anything jammed in the blades. If something's visibly there, turn power off (breaker or the shutoff box beside the unit) before you reach in, and only remove what you can see and grab without tools or taking anything apart.
Never spin the blades with your fingers while the unit has power. And don't do the internet trick of pushing the fan with a stick to "get it going" — it might start, but you've just confirmed a failed capacitor and put your hand near a blade that can start on its own.
3. Power and breaker
Check the AC breaker and the shutoff box beside the unit. If the breaker is tripped, reset it once — fully OFF, then ON. If the unit hums but the fan still doesn't spin, it's not a power problem.
4. Is the indoor unit blowing?
Go inside. Is air coming from the vents? If the indoor blower runs but the outdoor fan doesn't, the outdoor unit has its own problem. If nothing runs anywhere, see AC won't turn on.
What it usually is
- A failed capacitor. The small cylinder that gives the fan (and compressor) its starting kick. Very common, inexpensive, quick for a tech — and not a homeowner part; it holds a charge even with power off.
- A fan motor that's seized or burned out. Usually after a period of slow starts or a grinding sound.
- A contactor stuck or failed. The relay that sends power to the outdoor unit.
All three are inside the unit's electrical compartment. None are homeowner jobs.
Before you call
Leave the system off, and run the free troubleshooter. It captures what the unit was doing (hum, no fan, indoor blower yes/no), what you checked, and gives you a summary to read to the dispatcher — a technician hearing "hums, fan not spinning, indoor blower runs" already has a good guess and can bring the part.
Related symptoms
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