case fan won’t work

[PrimalPhoenix]

i’ve got a few old computers and i moved a 3 pin 12v case fan to a 4pin slot (looked on the internet and people say it’ll work) but i can’t seem to get it to work and i can’t find the sacred setting to make it act like a 3 pin socket. but there are only two cords coming out of the port it seems to be stuck with dust/grime but i can’t get it apart

[SenKa]

It's a dead fan. You can plug in a 3 in fan to a 4 pin header no problem. The 4th pin is just for finer RPM control.

[BobVonBob]

There may be a setting in your motherboard's BIOS to switch the header from PWM to Voltage control. These will usually be under something like "PWM"/"Digital" and "Voltage"/"Analog".

[Turtle Rig]

43 minutes ago, BobVonBob said:

There may be a setting in your motherboard's BIOS to switch the header from PWM to Voltage control. These will usually be under something like "PWM"/"Digital" and "Voltage"/"Analog".

Nice post, but most probably a dead fan like SenpaiKaplan said.

[LogicalDrm]

If you can find fan to SATA adapter, you can try with that. But by default any mobo header will provide 12V with 2 pins (DC and ground). 3rd is rpm sensor, 4th is PWM control. Meaning it's probably dead fan.