Argh! One of the fans in my Macbook is humming away on its last legs.
On the plus side, this fan controller is great for diagnosing the fan in question as there are two in the device..
Mine is a MacBook Pro Mid 2012 and the right fan.
The app could do with some better auto adjusting profiles based on temperature. It has three 'modes': AC-Power, battery and charging which can have separate profiles.
I can happily turn up the fans on any GPU / CPU intensive tasks now and keep the system cooler than Apple seemed to want to, prolonging the devices life in the long run!
For repairs on this laptop see iFixit!: