Is it safe to run this command? about smckit

[beltex]

Hello @josejmoran!

Sorry about the late response!

I'm surprised the HD fan would drop 0 RPM even though its not getting a reading from temperature sensor.

Can I use this command to set the speed of the HD fan: sudo smckit -n 1 -s 1102?

Yes! That is the correct command assuming you want to set the second fan.

Is it safe to run this?

There are no guarantees of course, especially when tinkering with hardware, but it should be a safe command to run. It simply sets the minimum fan speed. OS X itself will interject if it needs to raise it. In addition, it doesn't persist after reboot. Finally, you can always reset your SMC incase of any issues.

You might also want to cross-check with the Apple Hardware Test/Diagnostics incase there is some other issue here.