Symptoms
- One or more case fans don't spin at all when the PC is powered on
- Other fans in the case work normally
- Fan spun before but stopped after cleaning or moving the PC
- No unusual noise, just complete stillness from that fan
Likely causes
- CommonFan's power cable disconnected from the motherboard or a fan hubThis is easy to knock loose during cleaning or other work inside the case.
- PossibleFan connected to a header controlled by software or a curve that's keeping it offSome fan control software or BIOS settings can set a fan to 0% under certain conditions.
- PossibleFan motor has failedFans do wear out, especially cheaper ones or those in constant use for years.
- PossibleFan hub or splitter has failed, affecting multiple fansIf several fans stopped at once, the shared connection point is a likely cause.
What to do
- Power down, unplug, and check that the fan's cable is securely connected to its header or hub.
- If using a fan hub or splitter, check its own power connection to the motherboard or power supply.
- Check BIOS or fan control software for a curve that might be intentionally keeping the fan at 0% at low temperatures.
- Try connecting the questionable fan to a different, known-working header temporarily.
- If it still doesn't spin on a different header with confirmed power, the fan itself has likely failed.
- Replace the fan if it's confirmed dead, since most case fans aren't repairable.
Tools and parts
- Screwdriver
Replacement case fanSearch: “120mm or 140mm PC case fan”
Safety
Generally low risk
Generally low risk for a careful person. Stop if anything looks different from what this guide describes.