CPU fan speed not showing in BIOS or any software.

Jack_Wills11

Jack_Wills11

Jack_Wills11

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Joined
25 Jun 2019
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24
Hello everyone,
I was hoping I could get some help with my current situation.
I built my PC 4 years ago, but I have never been able to control/view fan speeds for the CPU or view any information about my AIO water cooler.

My system fans are working fine with PWM control and fan curves in the BIOS, however my CPU fans are not. Furthermore, I have no control of my H100i GTX cooler in Corsair Link. I've tried contacting Corsair over the years, but they haven't been much help at all. The device is connected using the included USB to micro-USB cable, however I can see no indication of it in device manager, and nothing regarding the cooler whatsoever in CL. I have disabled "USB selective suspend" in power settings, but still nothing shows. The two cooler fans are connected to the splitter, which connects them to CPU fan header 1, however, as shown in the photo below, there is apparently no CPU fan connected. I assume the fans run at 100% all the time, as I've never seen a change in their behaviour. Turning off "smart fan mode" in MSI Click BIOS 4 seems to have no affect on the situation.

There have been other things I've tried, but I'm struggling to remember them all right now, so I would appreciate any insight and help on the situation.

My specifications:
Intel core i7 4790K (not overclocked)
Corsair H100i GTX cooler
Corsair 16GB DDR3 Vengeance Pro (no XMP or overclock)
MSI Z97 Gaming 5 motherboard
MSI Nvidia Geforce GTX 970 (not overclocked)
250GB Samsung 850 EVO SSD (programs/boot drive)
1000GB Seagate Barracuda (games drive)
4000GB Seagate Barracuda (mass storage drive)
Windows 10 Pro 64bit

fl2aASX
https://imgur.com/a/fl2aASX :two images showing 'no CPU fan rpm' and 'no CPU fan detected'

Thanks,
Jack
 
@LuckyBenski

Thanks for the response. For convenience, I have underlined the things I haven't tried/I didn't know before.

FYI my CPU was probably quite toasty because I had the PC running for a bit beforehand, and my room gets very hot, because of the PC and my old monitor.

I few things you've mentioned I remember trying before.

So the fans I'm currently using are ones I bought after the cooler. I originally used the included fans, but swapped since they were too noisy. Both sets of fans displayed 0 rpm in BIOS.
Furthermore, both sets of fans had 4-pin connectors, where the splitter converts two-4-pin into one-3-pin connector. This splitter is attached to the radiator of the cooler. I have read about this change from DC to PWM control for fans in the BIOS before, but I can't find the option in my BIOS. If you could provide any insight, that would be helpful.

As for the USB cable, this comes directly from the pump and goes into a USB header on the motherboard. In the past I tried connecting the the cable to different headers, and tried to the front panel connector, but both showed no difference. The purpose (apparently) for the USB cable is to allow control of fan curves, pump speed, and changing the built-in RGB LED on the cooler. I don't have any of this functionality as the device is not recognised. I will try different headers/cable to see if it is visible again.

Another thing that I hadn't heard of before was following the third wire. I understand what you mean about it returning two signals, and that's why it drops to three wires. Are you suggesting that I have put the connector on the wrong three pins of the 4-pin connector? Because that might be a reason why there is no information about the fans in BIOS/softwares.

Thanks for your help. Hopefully you can answer my questions.
 
Tbh, I dunno how hot my room is. I come in here and its like an oven, unless I put the air con on. My room is also upstairs in a loft conversion so its hot up here all the time.
I'm planning to give my PC a good clean, because with exams and revision for the last few months, it hasn't had one in a while. It's possible the dust is suffocating it quite a bit. After the clean, I'll let you know if they temperatures are better.

As for the fan connectors, that's what I thought, because I knew there were guide notches. So that mean that all fans should be properly connected. I know that the last pin is for PWM control, so that doesn't explain the lack of RPM monitoring. What do you suggested I check for to solve the issue? @EsaT

EDIT: I've just checked CPU temperature with Speccy and its idling at 38 to 40C. That's fairly usual I would expect.
 
@labcoattech Yes sure, I can post photos of the fan connectors. I thought the exact same thing, as when I researched the issue, it said that PC's should never boot if no CPU fan is detected. So it's extremely odd that it says its disconnected in BIOS.

@freddie64 I can see how your method would work. Since the fan splitter is directly attached to the pump block, so connecting the block to a system header and the fans to a cpu fan header may work.
Also, I will try your optional extra step. However, surely this will just stop any control of the CPU fans altogether?
 
So replacing the CPU fan header with a system fan and the system fan header with the CPU fan pin has had successful results. In BIOS the CPU one fan has a visible rpm, meaning that there is nothing wrong with that header. However the system fan one header also has an rpm which suggests that the Corsair cooler is sending an rpm signal to the motherboard. So I’m not sure where the problem lies. I’m going to boot into windows now.

Update: bios is now saying 0rpm for the cpu fan (Corsair cooler)

Update 2: speedfan in windows is now saying 0rpm for the Corsair cooler.
 
So through trial and testing, I have concluded that the issue does not lie with any of the fan header; both cpu fan headers and all three system fan headers are fully functional.
Also, every case fan, including those on the Corsair cooler, are fully functional. They receive power, have PWM control and the RPM is visible.
The problems appear to lie with the cooler. As @LuckyBenski said, the splitter drops the tach wire on one of the fans on the splitter, however the splitter does take it from one fan as well as PWM control for both fans. This splitter goes into the pump block, and a three pin cable leaves the block. This would explain lack of PWM control, however doesn’t explain the lack of RPM monitoring. Furthermore, using the included usb header-mini usb cable or another usb-mini usb cable does not make the cooler appear under USB devices in device manager, or appear in Corsair link/iCue. This still means lack of RPM monitoring for the cooler, lack of PWM control, lack of pump speed monitoring, and lack of RGB control on the block. I am totally confuzzled.
 
Yeah that’s right. I would expect that cable to be a 4-pin, but it’s only 3-pin. I tried running the PC with one fan on cpufan1 and the other radiator fan on cpufan2 but then the cpu started to overheat (99°C) which made me realise you must still power the pump using that 3 pin. Therefore, I could get a new splitter, which connects the two fans to cpufan1 and connect the pump to cpufan2.

However, that means I still lack any control of my Corsair cooler with the CL software. That makes me speculate that there is something wrong with my cooler unit, because the miniUSB port doesn’t work (as it doesn’t appear in device manager, which it should) and I can’t monitor pump speed or change RGB.
 
@an0nym0us Yes sure. The only problem I might run into is setting its voltage to ad high as possible so the pump spins as fast as possible, because I have no way to monitor the pumps RPM, seeing as that 3pin from it is useless.
 
@Meddling-Monk ah ok. I was just about to say I don’t have sata power for mine.

@an0nym0us I think that’s how I’ll have to do it.

Right now I’m trying to purchase a fan splitter, however the one that I can get same day seems like it won’t work. Since a previous user said on this thread that a fan splitter drops the Tach wire (rpm) on one of the connected fans, otherwise the mobo would receive a confused reading. This splitter and many others don’t seem to be built like that.
 
So my splitter has arrived and the install is successful. However from boot, just in BIOS, my CPU is essentially idling at 47°C. I have no clue why it’s so hot. Even with CPU fans on 100%, it’s at 47°C
 
Ok, I’ll have to boot into windows and monitor idle and load temps there.

I could hear the pump working (occasional scratchy sound), but I have no way of setting it to 100% because the pump doesn’t obey the BIOS.

Ambient temperature could be the reason. My room is upstairs where it is warmer. I’ll put the AC on and see if it cools down at all (unlikely as my monitor is very hot).

Could also be to do with age of the dye, however I don’t recall it being that hot a couple of days ago.

I’ll let you know what the temps are like. I’m going to leave CPU radiator fans on a curve rather than 100%.
 
HWMonitor is saying 32°C for CPU, and that’s fairly steady.

GPU is showing 47°C, but I’m fairly sure it said that temp was for CPU in BIOS.

I’m gonna put it under load and see what I get
 
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