Toshiba Satellite -- fan malfunctioning

Nov 20, 2018
Hello comunity,
So I have a Toshiba Satellite L745-SP4023A running Windows 7 and I'm having issues with the motherboard fan.
I bougth it used from an IT guy, so the laptop was ussed in a office and does not have any scratch or signal of missuse un terms of being hit.

I understand the fan is automatic, when the computer heats up it starts spinning. But it happens that sometimes the computer starts heating up and it wont turn on. I just cant seem to predict when it will turn on and work properly and when it just wont start spinning even when internal temperature rises to dangerous levels.

I did download SpeedFan and started monitoring core's temperature, but the software wont recognice the computer's fan.

Also cant seem to find fan's hardware configuration on the bios, seems that bios does not have control over it (may the fan have its own temperature meter and be plugged directly to power source, bypassing motherboard?)

So, any advice on where to start? Certanly, the fan is not broken (as i first thought). The problem acctually is the umpredictability of its behaveour.

Thank you very much!

- - - - - - - -25/9 UDPATE- - - - - - -

Hey people, so I found a blogpost with a suggestion and I'd like to share it with you, I'm gonna test it right now and then post my results:
here's the walkthough:

it says "windows 8" but same options are available on win7
Nov 20, 2018
Thankz for the feedback people!
Unfortunately i have to disagree with your reply. Since the fan DO WORK sometimes. I just cant seem to get
control over it.

Just to put it simple. I've just turned on the computer and after surfing few website the fan started functioning, even when the computer didn't reached high temperatures (that i can perceve with my hands over the keyboard)

But then i run a heavy GPU consumming program such as a 3D videogame and the computer starts heating up, then the fan does not start functioning...

Sure i can DIY dissamble the computer, im used to fixing my desktop pc and even found tutorials on youtube on how to dissamble this particular notebook. But im pretty sure that the fun is not broken, I just cant figure out the pattern that it choses to turn on / off. I believe it is not plugged into the motherboard but directly into the computer's power source (although im not sure about that). I'm guessing that since there is no BIOS information on hardware or fan settings and since SpeedFan could not detect my laptop's fan.

I'd really appreciate any other suggestion or orientation rather tan replacing the notebook fan.

BTW, its a toshiba satellite L745 SP4203A

Once again, thank you very much! :)