Fan pin out

hey guys,
i wanted to program the firmware of my vertex k8400 to act like my other printer.

i mean exactly the fan switching , i wanted to do it [color=#BF00FF]automaticaly at 50°C[/color] to switch on the fan like other e3dv6 firmwares.

now heres the point, in the marlin fw from the k8400 is the hotend fan pin declared as “[color=#FF0000]fan_pin : -1[/color]” wich not work so far…
in the firmware of my other printer is there a “[color=#FF0000]fan_pin : 9[/color]” set.

what is the correct pin setting from the k8400?

so long Microfty