Chosen Solution
I bought a new left fan for my macbook as my old one was making the most horrible sounds. The replacement was very easy and went off without a hitch. After booting up the computer, the fan stayed stuck at 2000rpm, but was quiet and seemed to keep the computer cool enough. I didn’t worry. About two weeks later, I noticed that the computer was hot and I opened mac fan control and saw that the fan rpm was 0. I shut down the machine and opened it up. I briefly and carefully turned on the power, and saw that the fan itself wasn’t spinning. I took it all apart and inspected all connectors and everything seemed ok. I put it back together and still nothing. Pretty disappointed and worried now about melting my expensive work machine. What should I do?
I actually bought it via ifixit. They saw this post and are sending me a replacement part free of charge. Super-duper cool of them.
