Broke a hhd thermal sensor while swapping drives

JLG89 wrote:

To fix the screaming fan...

First, as mentioned, try smcFanControl: http://www.eidac.de

If that doesn't fix it, solder a 1/8W 2kΩ resistor between the two center wires on the 4-wire fan connector (leaving all the wires connected). This will drop the fan to about half speed, still a bit audible but nothing like the full-speed cyclone.

smcFan Control is NOT the right program for this. It sets a minimum fan speed, while what is needed is a program to set a max fan speed. Not getting any input from the thermal sensor of the drive, the SMC wants to protect the drive by maxing the fan speed. The right program is the free SSDFan Control, exirion, linked above by BDAqua. I know this is the right program from personal experience. I had the misfortune of breaking the contact to the thermal sensor off the logic board of my Mini. Until I put in place a permanent fix, I've been using SSDFan Control to deal with that.

I use smcFan in order to raise the fan speed when it is warranted.

Hello, a logic board will cost you near as much as a new Mini from Apple last I read. 😟

I'd not worry if it's working, but likely with the heat the tape will give way sooner or later, might consider Aquarium Silicon to hold it in place, it'll withstand 400°F. & contains do ingredients that conduct electricity once cured.

Other notes on the problem...

Tukaine

Sep 23, 2012 10:59 PM

Since the late 2009 iMacs came out, replacing the hard drive has caused the internal Hard Drive Fan to start running at around 6000RPM.

This is due to Apple replacing the external Hard Drive temperature sensor with a proprietary firmware and using the drives internal sensor.
Replacement drives do not contain the firmware to deliver temperature data on the temperature sensor cable.
When the iMac does not receive a good signal from the hard drive it puts the fan at full speed to protect the drive.

If you replace your drive, your iMac will initially seem fine, but soon the fan will begin to speed up to full speed. Resetting the SMC (System Management Controller) will have a temporary effect, but again the fan will speed up.

Fixes people have used in the past included:

• Using smcFanControl and the terminal to set a MAX speed for the fan and writing scripts to start this after every sleep/restart.

• Shorting the temperature sensor cable (Not a possibility on 2011 iMacs) this tricks the iMac into thinking the drives temperature is very low, hence slow fan speed.

Both these fixes are less then perfect and leave the drive in a dangerous situation with no protection from overheating.

Another option people try is other Fan Control software. These programs will not work for this particular issue as they often only control the base speed, and if they do control the fans actual speed they rely on the temperature reported by the sensor which is now incorrect.

HDD Fan Control

HDD Fan Control works to fix this issue by reading the drives internal temperature using the S.M.A.R.T protocol and set the fans actual speed to a value good to protect the drive. 
It runs at startup and continually to always control the fan correctly, prevent the loud fan noise and protect the drive from overheating.

Instead of HDDFan Control, get the free SSDFan Control...

http://exirion.net/ssdfanctrl/

To fix the screaming fan...

First, as mentioned, try smcFanControl: http://www.eidac.de

If that doesn't fix it, solder a 1/8W 2kΩ resistor between the two center wires on the 4-wire fan connector (leaving all the wires connected). This will drop the fan to about half speed, still a bit audible but nothing like the full-speed cyclone.

Great news I could help, thanks & good luck! 🙂