Question Fan issue on MSI B450M PRO-VDH MAX


Feb 10, 2019
I have ordered new case fans and installed them today I am aware that the model of motherboard that I have only supports 2 fans but I got a splitter so I could have 2 fans on each fan connector so 4 in total in the case. I installed the fans and when I turned on my PC the fans ran on 100% so very loud so I went into the MSI command centre to put the fan speed down but realised that I could only customize the fans that were connected on SYS FAN 2 and whenever I tried to put the speed down or do anything on the SYS FAN 1 it did nothing just kept running the fans at 100% even tho on the screen it says my changes have been applied I thought its a problem with the splitter so I tried switching them around same result I tried switching the fans around still same result the fans connected to SYS FAN 1 ran at 100% no matter what I tried anyone know what this could be?

Motherboard: MSI B450M PRO-VDH MAX
Fans: Corsair AF120 air series (4 of them)
Splitter: Cable matters PWM 2-fan splitter cable ( 2 of them)