I replaced my 2011 iMac WD HD with a WD, it might be a different model…..I used OWC for the process, they didn't say anything about the thermal sensor except to use their harness, which I could not fit.

And when I took the old HD out, I did not see the cable above they are showing at all? any ideas? Fans seem to be running a bit more……also I did not have the little foam for the back-side, will that hurt anything?

My TechTool Pro says all is well.

BTW-if you get the blinking folder, go online and get the tools to format disc and install your OS. (Disk Repair)

the guys at apple couldn't tell tell me that and I spent several hours looking at a blinking folder!