Question Front chassis fans aren't spinning, dimly glowing and letting out one long beep.

[KayyIsHere]

Build:
Corsair 4000D Airflow Case
ASUS TUF B450-PLUS Gaming ii
Ryzen 5 - 3600x
Nvidia RTX 3070
Corsair Vengeance RGB PRO 32gb (16 x 2) DDR4 3600MHz
Corsair RM850x 850, 80 Plus Gold
Corsair AF120, 120mm (Chassis Fans)

Okay so, I replaced my old PSU (VS650) with my new RM850x. The PC boots and everything, and every other fan runs, including the back case fan; but the front three chassis fans refuse to spin. They dimly glow and let off one beep for a few moments before stopping and repeating. The chassis fans are three pins plugged into a 4 pin splitter, which is then placed into the RGB header. I thought the splitter may have been damaged so I bought another, and the issue is still persisting. Tried resetting my mobo's bios to default and still nothing, tried controlling the fans manually (since I don't have an auto option.) Friend thought the cable wasn't plugged in properly, which it is. The long beep isn't listed anywhere in the TUF's manual guide either.

I wasn't having this issue before the PSU was replaced. I placed the old PSU back in but now the issue is happening with the VS650. I have no idea what to do. Anyone got an idea on what might be causing the issue?

Video of issue

 

[JohnBonhamsGhost]

The chassis fans are three pins plugged into a 4 pin splitter, which is then placed into the RGB header.

unless these fans are PWM(4 pin) their speed(RPM) is usually not negotiable.
the only option would be through 3pin voltage.

but if they are only connected via aRGB/RGB header their RPM is definitely not controlled via hardware or software.
there is no RPM data communicated through the LED header.

 

[KayyIsHere]

Ah, that makes sense. I'm relatively new to doing this sort of stuff on my own. If it doesn't go into the RGB header, then where would the fans insert into?

 

[drivinfast247]

Ah, that makes sense. I'm relatively new to doing this sort of stuff on my own. If it doesn't go into the RGB header, then where would the fans insert into?

Maybe a FAN header?

 

[KayyIsHere]

So, I'm just as dumb as I look. Placed the splitter into the clear part that says CHA_FAN and boom, it worked. Apologies for wasting everyone's time here. Thank you for your help.