Chosen Solution
I have a Mac Mini that I’ve recently upgraded by replacing the old HD with an SSD. Since then, the fan has been quite noisy and runs almost all the time. I figure I must not have handled dealing with the temperature sensor correctly or something close to that and it’s trying to cool down the SSD. I’ve just this week swapped out an old HD for an SSD in my iMac and the kit included the sensor in the link below. Can I use this same sensor and connector on my Mac Mini (which also uses an SSD connection) to keep the fan from running all the time?iMac Intel 21.5" and 27" (Late 2012-Late 2015) SSD Temperature Sensor
The Mac Mini and laptops use external sensors as well as S.M.A.R.T. services within the drive. You don’t need any extra sensor unit. At this point SMC services has either lost access to the needed sensor or a sensor was damaged. Your system is in CPU safe mode which ramps up the fan and lowers the CPU’s clocking to protect your system. So trying to offset this is not the correct direction. You should run diagnostics to identify the sensor. Restart your system and press the D key on your keyboard. Reference: Mac startup key combinations
The 2014 Mac mini does not have thermal sensors which are removable from the logic board - but some can be damaged during the upgrade process (they are on the logic board which you need to remove to install a 2.5” SATA SSD) I would suggest something like MacsFanControl to set the fan speed to the SSD thermal sensor (or another logic sensor which is working correctly)
