@briskspirit Yes. The fan is a 12V fan. I connected fan VIN (the red wire) to FAN1 V_FAN and fan ground wire to FAN1- . There is no jumper on FAN_VIN.
Hmm... This jumper selects the input voltage according to the schematic. It's not quite clear to me why my fans work, even though I have no jumper at all.
I will test it out this evening. I think you might have fixed the problem.
Thanks for your help.