MacBook Pro fan has NEVER turned turn despite the computer getting very hot at times.

SSL-ADT wrote:

Hello everyone,

I just had my MacBook Pro 16 M2 fixed after 2 1/2 years of issues. It had three different hardware issues. One of them being that the heat sensor never worked from the beginning, as I have never heat the fan running. The fan only working while running the diagnostics.

How can I test my computer now, especially during Canadian winter vortex, to see if that fan will finally turn on or not?

Someone online suggested using yes > /dev/null in Terminal, but it does nothing for me. Many suggest installing an app, but none of hose apps were found in the App Store.

Any idea? AppleCare+ failed to give me instructions of any kind, nor what they actually fixed.

Is there an on-going issue?

The diagnostics max out the fans due to the fact the OS is crippled—which typically sounds like a jet engine taking off.

The fans are notoriously quiet... If the machine was too hot it would shut itself down.

You can see your Recent Activity here—

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You can open the Activity Monitor.app and watch your CPU ramp up...

Stress test CPU from the Terminal.app copy and paste the following:

yes > /dev/null & yes > /dev/null & yes > /dev/null & yes > /dev/null &

use the enter\return key to proceed. I would enter this Command at least 4 times one after the other to test.

Let run for awhile.

From The terminal—To kill the process copy and paste one time:

killall yes

from my notes—

Fan speed for the M1, M1pro, M1max— I might suspect the same for your M2

if the system reaches 95 C or the  steady system  temperature above 60 C fans kick in at 1500 rpm.

See if this command works for M-series machine monitor fan (running job):

sudo powermetrics | grep Fan

(note: your psswd will not echo on screen type it in anyway, then to proceed use the enter\return key.)

control c   to kill the process

if not, for the M-series try

sudo powermetrics -s thermal -n 1

SSL-ADTW wrote:

hat are those command lines supposed to do?

I'm so glad I got my MacBook Pro back as it has the right keyboard layout unlike the interim MacBook Air. But, now I have to relearn how to type on it though.

If you have an issue take it —

In or out of warranty you can get a free over the counter 'Apple Service Diagnostics' test /assessment

Make an appointment for a "hardware issue"

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SSL-ADT wrote:

Okay, it is getting fairly warm now, despite being in cold weather. But, so far, no fan being on.

It wasn't only silent, there was absolutely no air coming out. In contrast, while running the diagnostic test, the fan was loud, and the air was wildly coming out of the hinge.

Your fans will turn on only if needed. If the computer gets too hot and the fans do not turn on the computer will slow its performance to reduce heating or it will shut down. Are you experiencing these symptoms? If not, the computer is not overheating and there is no need for the fans to turn on.

SSL-ADT wrote:

What? I just had the MacBook Pro 16 M2 repaired. It took 28 days to get it back. But, I have no clue if they have fixed my fan issue, as I can't get the fan to turn still. Others online often complain of fan noise. Me, I complain about never hearing the fan or feeling any air, even after pushing a constant of 97% of CPU power for a while.

I did have it checked at a Genius Bar, but they could not detect anything wrong, other than my left speaker rendering distortion about a year ago.

The fans can be very quiet unless they are running at max speed. The Apple Diagnostics will test both high & low fan speeds so if the diagnostics pass, then the cooling system most likely is working properly.

If you installed a third party app which manipulates the fans, then all bets are off.

You can use Macs Fan Control to monitor the fan speed, but you should leave macOS to manage the fan speed. I run it directly from the Downloads folder and if I deny it to update or relocate it, then it doesn't install anything else except for the app's .plist preference file which is typical for any app running on macOS.

It can be hard to make an M-series Mac run hot enough to hear the fan. You can try using the built-in Chess app

and have the computer play multiple games simultaneously against itself....set the difficulty to high. I had an Intel Mac's fans run where I could hear it with just two Chess matches going, not sure what it may take for an M-series Mac.

What parts exactly did Apple replace? Usually the only time multiple parts are needed are when people don't deal with an issue right away & a second issue develops, or it is due to accidental damage. In my 25+ years of experience it is usually due to the latter.

SSL-ADT wrote:

In contrast, while running the diagnostic test, the fan was loud, and the air was wildly coming out of the hinge.

as you would expect using the diagnostic.