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How To Fix AIO CPU Fan Not Working

Learn how to fix the issue by replacing the power supply, reconnecting the cooler, and more.

AIO, or an All-In-One cooling system, is a liquid-based thermal solution for your CPU. If the AIO fan stops working, the CPU temperature might rise to a level that could cause permanent damage to the processor and other internal components. Users often face CPU fan errors that may be mainly attributed to issues with the fan or its controlling system. Therefore, to keep the temps down, you must learn about how to fix the AIO CPU fan not working issue. 

You might be interested in learning about how long AIO coolers last

Key Takeaways

  • CPU fan not working is a common issue that can cause your PC to overheat and shut down, or it can also cause damage to the components.
  • The CPU fan might stop working for several reasons, including dust clogging, connection to the wrong header, low CPU fan rpm limit, faulty PSU, outdated BIOS, broken CPU fan, or a defective motherboard.
  • The issue can be resolved by cleaning and lubricating the fan, utilizing another header, updating the BIOS, setting a suitable CPU fan rpm limit, replacing the PSU or the fan itself, or getting a new motherboard.

Why Is My AIO CPU Fan Not Working?

AIO Cooler
AIO Cooler Installed Inside Case – Image Credits [Tech4Gamers]
AIO cooling package usually consists of a fan or multiple fans, a pump, pipes, and a reservoir. If the CPU fan stops working due to some reason, the system will usually raise a CPU fan error. But it is quite possible that you don’t get any CPU fan error even if the fan is not spinning. In that case, you must notice that the CPU fan is not working physically.

The CPU fan is controlled and managed by the BIOS. It might stop working for several reasons, including a misconfigured or outdated BIOS, a broken fan, faulty headers, or issues with the motherboard.

It is usual for the CPU fan to stop spinning for a while when the temperature goes below a specific limit. But it is an alarming situation if the fan stops spinning completely.

Modern PCs usually have a built-in safety feature that forces them to shut down if the temperature rises above a specific limit. But this still doesn’t guarantee that the components will not get damaged. Also, learn about how to lower CPU temperature to prevent this from happening. 

Also Read: How To Remove AMD CPU Fan 

How To Fix The AIO CPU Fan Not Working ISSUE?

Physical inspection is the first step towards solving the issue of the AIO CPU fan not working. CPU fans often get jammed or clogged due to debris or dust accumulation. This could prove to be risky as the fan might stop working entirely. 

Dusty CPU fan
A dusty CPU fan – Image Credits [Quora]
Regularly checking your PC fan for dust accumulation and cleaning it periodically is recommended. You may also want to lubricate the fan bearing that helps it spin by putting some drops of mechanical oil into it. Make sure to read our guide on how to clean PC fans

Also Check: AIO Vs Air Cooler

Also, ensure that no wires entangled with the CPU fan prevent the fan from spinning. CPU fans generally produce less torque, so even the lightest wires can stop the fan from turning.

Your PC fan is also programmed to spin faster when the CPU runs games or resource-hungry applications. Start a game and look inside the CPU to check whether the fan has started spinning faster. If you don’t observe any change in the spinning speed of the fan after some time, chances are there is something wrong.

If such is the case, you can further troubleshoot the issue.

Connect The AIO Pump Correctly

The first thing to make sure of when using a liquid-cooled CPU is to connect the AIO pump correctly. The complete AIO setup usually has 3 or 4 cables attached to it, including 3-pin and 4-pin connectors, SATA connectors, and a USB connector.

  1. Connect your AIO pump to the AIO_PUMP header.
    AIO_PUMP header 
  2. If there is no AIO_PUMP header on your motherboard, you may connect the AIO pump to SYS_FAN or CHA_FAN instead (The header must be set at 100% speed in BIOS’s settings).
  3. Connect the 3-pin connector to the CPU_FAN header on your motherboard.
  4. Connect the 4-pin splitter connectors to the radiator fans.
    AIO Pump
    AIO Pump headers 
  5. Connect the SATA connector to any free SATA cable on your motherboard.
    AIO connectors
    AIO connectors- Image Credits [Corsair]
  6. Connect the USB connector to any free USB header on your motherboard.
  7. The system may generate a CPU Fan error even when the AIO Pump is connected to the AIO header. Attach any fan to the CPU_FAN header to remove that error.

Mount The CPU Fan Correctly

Usually, the CPU fan stops working when it isn’t correctly connected to the CPU_FAN header. Ensuring that the fan is correctly mounted in its place and connected to the proper header is of paramount importance. To mount the CPU fan correctly:

  1. Ensure that the CPU fan is appropriately fixed in its place.
    CPU fan configuration on the motherboard 
  2. Check whether it is connected to the correct header, i.e., CPU_FAN header.
  3. Ensure the header is connected in the correct orientation corresponding to the specific pins.
    4 pin header
    4-pin header orientation 
  4. Usually, the CPU_FAN header is towards the upper right corner of the motherboard; however, its position may vary depending on different models and brands.
    Motherboard Schematic
    Location of CPU_FAN header on the motherboard 
  5. Connect the cables to the header in such a manner that they aren’t loose.
  6. If you are still in doubt regarding the location of the CPU_FAN header, consult your motherboard’s manual or try checking for the printed indications on the motherboard.
  7. You can also visit the manufacturer’s website for related guidance. For example, ASUS users can see the support page for further guidelines.

Also Read: How To Remove Intel CPU Fan/Cooler? Step By Step

Set A Suitable RPM For The CPU Fan

If the fan is spinning at a very low speed, the motherboard may fail to recognize it. To avoid that, reduce the CPU fan’s lower speed limit or ignore it entirely from the BIOS settings.

  1. Enter into the BIOS settings menu by pressing and holding the F2 button on the keyboard while pressing the power button (The BIOS key may differ depending on the machine you are using.)
  2. If you cannot enter the BIOS using this method, go to Settings and click Update and Security.
  3. Click on the Recovery option and then select Restart Now.
    Update and Security settings
    Update and Security settings – Image Credits [Tech4Gamers]
  4. Now click on Troubleshoot and select Advanced Options.
  5. Select the UEFI Firmware Settings option and click on the Restart button.
    Advanced options
    UEFI Firmware Settings – Image Credits [Tech4Gamers]
  6. The system will enter the BIOS settings menu after rebooting.
  7. Locate the Advanced Mode inside the BIOS settings and go to the Monitor tab.
  8. Go to the Fan Control section.
  9. Go to CPU Q-Fan Control or Q-Fan Configuration.
    CPU Fan speed control
    CPU Fan speed control – Image Credits [Tech4Gamers]
  10. Now, set the CPU Fan Speed Lower Limit to a lower limit, like 200 rpm, or choose the Set to ignore option.
  11. For some motherboards, the option of Fan Speed Control might be under the Monitor section.
  12. Save the settings after you have made the required changes and reboot your computer.

Also Read: AIO Vs Custom Loop Liquid Cooling 

Update The BIOS

An outdated BIOS can result in several issues related to your PC, including the PC fan not working AIO. Updating BIOS might be tricky, so be very careful while trying to update the BIOS. In case you want to reset BIOS, we have a guide on it as well. 

It is recommended that all personal files should be backed up before proceeding to update the BIOS. You must check the current version of BIOS on your system before trying to update it. If the BIOS is already up to date, move on to the next fix.

  1. Launch the command prompt by typing cmd in windows search.
  2. Enter the command “wmic bios get smbiosbiosversion” and note down the BIOS version.
  3. Exit all the running applications.
  4. Disable the antivirus by searching for Security and Maintenance and then clicking the option of Security to access antivirus settings.
    Security and Maintenance Settings
    Security and Maintenance Settings – Image Credits [Tech4Gamers]
  5. Also, temporarily suspend the BitLocker drive encryption by going to Manage Bitlocker and clicking the Suspend Protection (Make sure you have the Bitlocker recovery key before suspending Bitlocker).
  6. Now go to your motherboard manufacturer’s official website; for example, HP users can visit the HP support page to download the latest BIOS file.
  7. Choose the model and the operating system of your PC.
  8. Download the BIOS file on your PC.
  9. Now, open the BIOS file once it has been downloaded and follow the instructions for installation.
  10. Click Update when the HP BIOS Update and Recovery window appears.
    Update BIOS
    Select Update – Image Credits [HP]
  11. Click the Restart Now button in the next window.
  12. Click the Apply Update Now button.
  13. Wait for the BIOS to be installed completely.
  14. Once the installation is complete, reboot your PC and enable the antivirus and Bitlocker protection.
  15. If you face any issues while updating the BIOS, visit the manufacturer’s support page for guidance (For example, HP users can visit the HP Support page).

Replace The Power Supply Unit

Most desktops have a Power Supply Unit (PSU) that supplies different voltages ranging from 3 to 12 Volts to various components on the motherboard. Your fan takes 5 or 12 Volts, so your CPU fan will not work if these supplies face issues.

If you hear beeping sounds or more than one component is not working, your PSU may be faulty. If your computer shuts down immediately after booting up, this is also an indication of a faulty PSU. In this case, you need to replace the PSU, as your AIO CPU fan might not be working due to it. 

PSU to solve computer repeatedly restarting
Antec EAG Pro 650W PSU. Image Credits: Tech4Gamers

Laptops usually have the PSUs integrated into their motherboards, so you would need to change the motherboard for laptops. Also, ensure you get a compatible PSU for your computer with similar supply ports to the broken one.

Replace The CPU Fan

If you have tried all these fixes and your CPU fan is still not working, chances are that your fan CPU fan is broken. One way to ensure the CPU fan is faulty is to connect your fan to a PC instead of a working fan. If the fan is still not spinning, the fault lies in your CPU fan, which you must replace.

Replace The Motherboard

If you have attached your CPU fan to another PC in the place of a working fan and the fan starts spinning, your motherboard is faulty. Another way to check this is to connect a working CPU fan to your motherboard. If it doesn’t work, you can be sure that the motherboard is faulty and that you must replace it.

Gigabyte Z790 Aorus Elite AX motherboard
Gigabyte Z790 Aorus Elite AX motherboard. Image Credits (Tech4Gamers)

Also Read: 280mm vs 360mm AIO 

Ensure you get a motherboard compatible with your fan and the other components to use the same components on the new motherboard and save extra costs. While removing the motherboard, you will also need to remove the GPU. Make sure you learn how to do it, as you can damage the components otherwise. 

Final Word

This was everything you needed to know about the AIO CPU fan not working issue. If you still cannot solve this issue, visit the support page of your motherboard’s manufacturer for further guidance and troubleshooting.

Frequently Asked Questions

Why isn’t my CPU fan working?

Your CPU fan might be clogged due to dust and debris accumulation which may prevent it from spinning. Other possible reasons include the fan connected to the wrong header, low CPU fan rpm, faulty PSU, outdated BIOS, broken CPU fan, or a faulty motherboard.

How to fix the issue of the CPU fan not working?

Cleaning and lubricating the fan mostly resolves the problem. Other fixes include connecting the CPU fan to another header, updating the BIOS, setting a lower CPU fan rpm limit, replacing the PSU or the fan, and replacing the motherboard.

Will my PC work without the CPU fan?

No, your PC won’t work without the CPU fan and will throw a CPU fan error. In some cases, the PC might turn on, but it will soon shut down when the temperature of the CPU increases.

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