Fan splitter only powering one fan.

[traviskhdiamond]

I just bought a Define Nano S case, and I set it up yesterday. Everything went well, except that I cannot get both of the stock fans to work at once. I am using the supplied fan adapter cable, but only one side of it works. If I trade the place of the two fans in the splitter the one that previously didn't work, works. I have a ROG Strix Z370-I Gaming motherboard, if that makes any difference. The fan splitter and both of the fans use three pin connections.

 

[The Paladin]

have you tested each fan on the header separately to confirm both fan are functional ?
Are you sure you plugged the 3 pin into connector properly ?

 

[traviskhdiamond]

have you tested each fan on the header separately to confirm both fan are functional ?
Are you sure you plugged the 3 pin into connector properly ?

Yes, both fans are functional. The splitter is plugged into a four pin socket, but from what I found online that should be okay. I have tried unplugging and re plugging everything I can, but nothing helps.