Hello all,

My motherboards (gigabyte Z97n-wifi) sys_fan (4 pin pwm) port does not send a pwm signal when only the pwm and tach pins are connected, when all 4 pins (pwm, tach, +12v, ground) are connected it does give a pwm signal.

Additional information:


  • When I connect the pwm header to the cpu_fan header it works. (with only the tach/pwm singal).
  • I am connecting a pwm splitter (for my fans) to the port which uses a molex adapter for power (for the +12v/ground connection).
  • It seems that I can read the rpm from the signal (which is constanly at its max) but cannot edit it, not in gigabyte SIV nor in the BIOS.
  • My BIOS version is F4, I dont really like updating this but if this could solve it, I would reconsider it


I dont know how to solve this issue but was thinking about maybe chaning the sys_fan port to a cpu_fan port, is this possible?Thanks in advance for the help.

Kind regards,

Rienkrk