MacBook Pro 2015 Fan Problem

[Bigyid]

Hi, I have a 13” MacBook Pro 2015 and the fan seems to be misbehaving! MacBook shuts off randomly so I thought it might be over heating.

I ran a diagnostic test and indeed it states there maybe a problem with the fan! So I decided to have a look to see what’s happening. At first when I powered it on the fan wasn’t working, so I thought that’s the problem, anyway thought I would unplug battery from board and unseat fan plug and reconnect in case it was loose.

Now put power back on to board and powered on and fan starts then just goes off! Could it be the fan is just knackered even though it starts then stops?

 

[iMacDragon]

Could suggest the speed sending wire is broken, perhaps? Just a guess.

 

[okkibs]

I assume going off means it stops? That is normal, this model stops the fan unless the temperatures get high. You'd have to at least be using it actively to get it to spin. If going off means it keeps blasting at full speed, then that could be a damaged temperature sensor (cable). In that case the Mac can no longer read the temperature and leaves the fan running at full speed for safety.

 

[Bigyid]

I assume going off means it stops? That is normal, this model stops the fan unless the temperatures get high. You'd have to at least be using it actively to get it to spin. If going off means it keeps blasting at full speed, then that could be a damaged temperature sensor (cable). In that case the Mac can no longer read the temperature and leaves the fan running at full speed for safety.

So yes the fan starts up fine then it just stops within about 10-15 seconds and stays like this and doesn’t start back up. So because fan isn’t running the CPU must shut down MacBook to prevent any damage, it won’t stay on longer than 5 minutes before it shuts down and the heat sink is too hot to touch (not surprising as the fan isn’t working)

 

[okkibs]

Doubt it's a problem with overheating. The CPU will simply slow down to avoid overheating. Open Terminal and copy paste this and press enter:

yes > /dev/null

This creates 50% CPU load on that Intel dualcore by endlessly writing the word "yes" into oblivion, thus the CPU will generate extra heat. When you run this the fan should turn on within 1-2 minutes confirming that this isn't a heat issue.

Apple has literally set the fan to stay off until the temperatures are approaching 90-95 degrees C, so it's absolutely normal behaviour for this model to heat up and the fan remaining off. I have the same model sitting on my desk.

If the fan still doesn't spin, you can open a second Terminal window/tab, and copy paste that command there as well to double the CPU load from 50% to 100%. The fan will spin up within 30 seconds.

Quit Terminal and confirm "terminate processes" to stop the CPU load afterwards.

/Edit: You need to visually check if it's spinning, it might not spin very fast and might not be audible for a while.

 

[Bigyid]

Doubt it's a problem with overheating. The CPU will simply slow down to avoid overheating. Open Terminal and copy paste this and press enter:

yes > /dev/null

This creates 50% CPU load on that Intel dualcore by endlessly writing the word "yes" into oblivion, thus the CPU will generate extra heat. When you run this the fan should turn on within 1-2 minutes confirming that this isn't a heat issue.

Apple has literally set the fan to stay off until the temperatures are approaching 90-95 degrees C, so it's absolutely normal behaviour for this model to heat up and the fan remaining off. I have the same model sitting on my desk.

If the fan still doesn't spin, you can open a second Terminal window/tab, and copy paste that command there as well to double the CPU load from 50% to 100%. The fan will spin up within 30 seconds.

Quit Terminal and confirm "terminate processes" to stop the CPU load afterwards.

/Edit: You need to visually check if it's spinning, it might not spin very fast and might not be audible for a while.

When I started MacBook up and hold down “D” it ran a diagnostic and came up with the following.

 

[okkibs]

Sometimes diagnostics will spit out random error codes that can be ignored. Try the test from my previous post to confirm it's broken. The Mac has that safety shut off if it does overheat. If the fan really does not work, there are two possibilities, either a simple cheap fan replacement does fix it immediately - or the issue is actually with the logic board itself that has the logic/controller on it for turning the fan on. If that is the case, the fan replacement won't help, but you won't know until you have tried that. Sadly that model only has a single fan, in models with two fans you could just swap the fans around (Edit, actually that is not entirely true, the fan connectors aren't always the same and could prevent swapping).

You can buy a replacement fan from amazon/ebay/ifixit, somewhere you can do a hassle-free return if the problem ends up persisting.

An issue with the logic board would require sending it in to be repaired, for example https://rossmanngroup.com/ is highly recommended. You can call and ask for a ballpark estimate beforehand, I'd estimate 100 bucks or so at least.

It might not be financially viable to get that repaired. You could sell it as is with the error code screenshot for 100 bucks or so and let someone else deal with it. The fact that it still boots up means there will likely be someone out there who will take a chance that it's easily fixable.

In my opinion, since I have this Mac myself and upgraded it with a fast 2TB SSD... I think that Mac has really reached end of life now, it's super slow under Monterey even when it works normally.

You could alternatively use it as a desktop computer and literally fix a 120mm fan to the heatsink yourself that you plug into a 5V USB power supply or into the Mac's USB port. Then the Mac won't overheat and you can just keep using it, but the bottom plate will need to remain removed and the extra fan needs to be running.

 

[Bigyid]

I think it might be logic board

Just got a new fan and same thing happens, it starts spinning then stops, I replaced the thermal paste and it’s staying on longer than it was about 10mins so far and no fan running. I have 18mins left of Mac OS installation so will see if it finishes before shutting down.

 

[Bigyid]

Got it up and running still no fan working, installed Macs Fan Control and put it to full blast and nothing

 

[ilikewhey]

when was the last time the cpu paste was reapplied.

 

[Bigyid]

when was the last time the cpu paste was reapplied.

Today because I changed fan and you have to take heat sink off so cleaned it and put new thermal paste on.

 

[Bigyid]

Still getting “there maybe an issue with the fan” when I run diagnostics but it’s staying on so far without shutting down.

 

[real_mon2]

Post the model from the bottom plate. It will be A1466, etc marked. Also if you can find it, interested in the 820-**** number of the logic board. Then we can review the schematic to study this fan circuit. Do you have a multimeter?