One CPU fan always at max RPM

[carnevalep7]

I've got a cooler master masterliquid 240 mounted on a msi z170a m7 MB and there is always one of the two fan running at max rpm, the other one works fine as it should.
i connected them to the MB with the cable that i found in the package, that doubles the outputs.
i've even tried to connect them directly to the MB but there aren't enough pin to connect them rightly but it didn't change nothing.
Smart mode is already active.

 

[AniChatt]

So you have tried to connect two fans with the fan splitter cable and connected it on the motherboard fan header? So the mobo sending similar signal to fan and one fan spinning at intended speed but the other one is still spinning at top speed it is not possible unless one fan pwm function is not working at all. Tell me if it is correct or not.
Just to check your mobo should have two fan port for connecting cpu fans, one is cpu fan and the other is cpu optional fan. First connect these two fans (cooler) on these two mobo then enable yur smart fan control to test if these are working correctly or not.
There is a option of calibration of the fans in smart fan control menu. Calibrate fans first before applying any setting. I think there is a issue in fan calibration.
And finally make sure to power the pump in designated aio pump header on the mobo. Otherwise mobo may control pump voltage too. Your pump supposed to get a specific voltage to operate properly.

 

[carnevalep7]

I had to connect the fan with a splitter because as you said i've got only two port, and one is occupied by the liquid pump(i don't know how it's called).
Already tried with the auto tuning but nothing changed, so yes, i've the two fan connected with a splitter and it does send two different signal, do you think that it could be the pwn not functioning?

 

[AniChatt]

I had to connect the fan with a splitter because as you said i've got only two port, and one is occupied by the liquid pump(i don't know how it's called).
Already tried with the auto tuning but nothing changed, so yes, i've the two fan connected with a splitter and it does send two different signal, do you think that it could be the pwn not functioning?

Ok understood. Before drawing any conclusion pls swap the cables, I mean put the pump header in the fan header and put the splitter cable in the current pump header. Then calibrate you smart fan control to check is still it is the same fan causing this issue or not.
However how many pins you have on mobo fan headers? And your mobo has only two fan connector? Your mobo model?

 

[carnevalep7]

The mobo is the msi z170a m7.
I've swapped the cables and nothing changed, then i swapped the cables in the splitter and now the two fan are syncronized (i guess), but they run at 800rpm minimun and never stop, anyway if before swapping cable one of the two fan usually stopped, now it doesn't, but it seems that the other one have slowed down.
I also found that probably on the msi command center the fan that's running at 2800rpm it's the pump, because it doesn't have the pwm, then, as i see only one more fan on the command center i don't know which one i'm looking, or if it's both of them synchronized.

 

[AniChatt]

The mobo is the msi z170a m7.
I've swapped the cables and nothing changed, then i swapped the cables in the splitter and now the two fan are syncronized (i guess), but they run at 800rpm minimun and never stop, anyway if before swapping cable one of the two fan usually stopped, now it doesn't, but it seems that the other one have slowed down.
I also found that probably on the msi command center the fan that's running at 2800rpm it's the pump, because it doesn't have the pwm, then, as i see only one more fan on the command center i don't know which one i'm looking, or if it's both of them synchronized.

It seems you have messed and misinterpreted. the pump will always run at constant voltage. Never try to reduce or control this even by mistake. Regarding the other fan, since two fans are connected via a single cable to the mobo cpu header then mobo sees these two fan as a single fan. You can not see two fan now. And these two fans should be in sync by default becs they are both getting same signal via same cable (slitter).
CPU fan will never stop this is the way how cpu fan headers are designed. SO no you can not simply select to turn it off. You can if you have plugged it in a system fan header but NOT RECOMMENDED AT ALL. So keep the slitter in CPU fan header.

 

[carnevalep7]

Yep i did, i'm sorry that i waste your time, no i won't try to connect them to the system fan header, thank you very much