iMac fan runs continiously
What is causing my iMac fan to run constantly
iMac 27″, macOS 12.0
Question marked as
By default the Fan(s) "depending on the model" always run when the iMac is on.
If the Fan(s) are running full blast, then try resetting the SMC.
https://support.apple.com/en-us/HT201295
If the SMC reset does not help and the iMac has been repaired or you have done some type of DIY hardware upgrade? Then there is a pretty good chance that a temperature sensor is either disconnected or has been damaged.