Just replaced the drive in a 3.1GHz i5 27” Mid 2011 with a bad 1TB Seagate drive. Thought Apple had a replacement program, but they told my customer NO. (they say a lot of things lately). Ok so when I took it apart there was no thermal sensor on the HD, nor a cable. SO I put in a Black WD 2TB. When reassembled, high fan noise on the middle HD fan. So I put on a fan regulation program, dialed down the HD speed and all is fine. Q - with no cable and no sensor… why did this happen?