MacBook Pro fan is not running on default settings regardless of how hot it gets

Question

I have a MacBook Pro (Retina) and I am noticing that the fan is not running at all even though the temperature gets to more than 60c and the system starts lagging. I had iStat Menu installed and when I switched from default to manual setting and set the speed the fan would start spinning.

Now I am using the manual setting and running it on 4000rpm and the temperature gets to between 40c-50c. I am concerned about why this is happening? Why does it not work automatically on the default setting even though it gets so hot to the point that it starts to lag. Is it a software bug or does my fan have some sort of hardware issue?

One more thing: when I adjust the fan speed slider from 4000 to 2000rpm the fan suddenly stops working and I can not hear any sound and the temperature starts to heat up.

I also uninstalled the iStat Menu to see if it makes a difference, but the fan still doesn't run no matter how hot the laptop gets. Please advise the possible solution to this problem.

I am running Mac OSX 10.11.

P.S. Sorry for my bad English.

Answer 1

Have you tried resetting the SMC?

For MacBook Pros, MacBook Airs, and MacBooks where you can’t remove the battery on your own (i.e. it's a built-in battery), here’s what you do:

1. Shut down your computer
2. Keep the MagSafe adapter (or power cable) plugged in.
3. Press at the same time shiftoptioncontrol (on the left side of the keyboard) and the power button
4. Let go
5. Turn your computer back on with the power button.

Let us know if this resolves your issue.

[UPDATE]

A lot has happened in the Mac space (incl. the various MacBook models) over the past couple of years and the process for resetting the SMC can differ now due to additional criteria (e.g. if there's a T2 chip installed, etc).

For the latest advice refer to How to reset the System Management Controller (SMC) on your Mac on Apple's website.