Chosen Solution

Dear all, I encountered a very odd problem recently while trying to upgrade my mothers Mac Mini. I wanted to install a SSD drive and first purchased a Crucial M4 128 GB. Following the excellent manual provided on this website it took me just 15min to do so. Mac OS installed perfectly but the Mini would always shut down while installing Windows 7 via Boot Camp. Thinking this was an issue with the Crucial SSD, I exchanged it for a Samsung 840. The installation of Windows 7 worked, but once I wanted to install drivers, the Mini shut down again. I discovered that when the SSD is in the Mini, the fan won’t work and the sensor correctly reads 0 rpm. Bootcamp seems to have a higher cpu load so that it shuts down quicker. When I did a quick stress test in Mac OS, the mini would shut down after a few minutes too. (Apple Hardware Test (AHT) also tells me that the Fan Motor does not work) Now comes the strange part. First I assumed I broke a cable or the temp sensor (although I used extreme caution and would describe myself as experienced with these kind of tasks). However, when I reinstall the old 160GB HDD, the Fan will work perfectly, without any errors in AHT. Does anyone have a clue why the fan spins normally with the original HDD installed and won’t even start with 2 different SSDs? I want my mom to profit from the superior SSD speed, but when the fan simply won’t work, this is not an option. Kind regards from Germany, Daniel

The fan should spin at max RPM if any temp sensor is not detected, as a failsafe. Is something interfering with the fan mechanically? The SSD should draw less power than a regular HDD, so I am wondering if this might be mechanical and not electrical. You can run the unit without reassembling it to see if a cable or the SSD housing is interfering. I can’t image the SSD housing is causing a problem, but you never know.

You may have solved this, but I had the same problem (fan not working after SSD upgrade). In my case, it was the pesky little fan connector on the mother board. It does not snap in firmly, and had, just barely, slipped out. Plugged it in firmly and added a tiny piece of tape. Fixed.

did a upgrade to my mac mini same problem

Same problem here. Any thoughts?

Did anyone here try an SMC reset? https://support.apple.com/en-us/HT201295