Chosen Solution
Hello. I changed the hard drive (1TB original to Kingston SSD 960 GB) on my iMac EMC 2544, Late 2012 13,1. After that, I had exactly the same problem. iMac fan starts after shutdown Fan runs after shutdown and when iMac goes into sleep mode. Can you advise me of anything? After installing the old hard drive back, nothing has changed. Update (05/01/2017)
How about installing this app so we can see what your systems thermal management is up to here: TG Pro. Paste a full screenshot of the main screen so we can see all of the sensors in a fresh answer.
