I have a Phanteks Ethoo Pro M Case, an ASUS Z390-A Mobo, and 5 PH-F140SP LED case fans. I've connected the fans' 3-pin plugs to mobo's fan headers. but I can't figure what the second wire (coming from the fan) is for, or what it connects to. So I wrote to CS and this was the response I received (verbatum):
Any help deciphering their response and resolving this issue would be greatly appreciated.The second wire you will able to connect the switch cable inside the fan's package and you will able to turn on of turn off the LED inside the fan .