MSI GT70 ms-16f3 mainboard fan issue

After the computer boots up, I can enter the BIOS, but the laptop fan runs for 5 seconds fast, 5 seconds slow, and then shuts down after about 40 seconds. I bought a new fan and tried it, but the problem remains the same. What could be the problem?
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@serkan25205 does your computer overheat and shut down? Do you use a temperature monitoring software? What temps does it show?

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The computer shuts down before I can even enter Windows, so I can't see the temperatures. There's no section in the BIOS related to fans or heat. My keyboard, USB, and other connections work, so I don't think the EC chip is the problem. When I measure the motherboard pin where the yellow fan cable connects with chassis, I see a short circuit. Is this normal? Is there a link to the schematic or repair documentation for the MS-16F31 motherboard?

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