Yeah so my iMac is in pieces right now due to a harddrive replacement, i think the iMac is a Late 2009 one, 2374, i bought it in Februari 2010 and it was the latest one, so yeah i think it is the EMC 2374. Anyways, i have not put the iMac together yet since i don't have the tools to assembly it and i want to restore from my backup before i put it back together if for some reason something fail, so i don't need to disassembly it once more. So i connected my Apple Cinema Display to the iMac and i am now restoring from my backup, the thing is, the fans run at a crazy RPM right now, the weird thing is, my new harddrive had a connection for the thermal sensor, like the standard one that i replaced. My local Apple store said i would have to buy a separate thermal sensor because they claimed that none of the internal harddrive temp sensors worked, only Apple provided those harddrives with a connection for a temp sensor, anyway, the Seagate i bought (not from Apple) had a thermal connection, my other WD drives does not have a connection for the thermal sensor, but yeah, my new Seagate ST1000DM003 have one and the iMac´s internal temp sensor is now connected to the harddrive. But i don't know if it works in the iMac since the fans goes like crazy, but there also seems to be a thermal sensor in the LCD and that one is obviously not connected and that makes the fans spin at max?