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How to troubleshoot fan and AIO Issues

If you're experiencing problems with your system's fans or AIO liquid cooler, use this guide to identify and resolve the most common issues.

Updated over 10 months ago

Common Symptoms

  • Fans not spinning

  • AIO pump not running or making noise

  • High CPU temperatures

  • BIOS or software not detecting fans or pump

  • RGB not functioning properly on fans or AIO


Basic Checks

Before diving into more advanced troubleshooting, confirm the following:

  1. All power and data cables are securely connected

    • For AIOs: Ensure the pump power cable is connected to CPU_FAN or PUMP_HEADER.

    • For fans: Confirm connections to FAN headers on the motherboard or fan hub.

  2. No bent pins or damaged connectors

    • Visually inspect fan headers and connectors.


Fan Troubleshooting

1. Fan Not Spinning

  • Check header detection: Confirm the fan is visible in BIOS or monitoring software.

  • Test on a different header: Plug the fan into another known working fan header.

  • Inspect for obstructions: Ensure cables or other objects aren't blocking fan blades.

  • Test with a known working fan: Helps isolate if the issue is the fan or the motherboard header.

2. Fan Spinning at Full Speed or Not Responding to Control

  • Control mode mismatch: Set fan control in BIOS to PWM or DC based on the fan type.

  • Software conflicts: Ensure only one fan control software is active (e.g., Armoury Crate, iCUE, CAM).

  • Profile reset: Restore BIOS fan settings to default and reconfigure.


AIO Troubleshooting

1. Pump Not Spinning / No Activity

  • Verify power source: Make sure the pump is connected to a dedicated PUMP header or SATA power.

  • BIOS check: Some AIOs don’t report RPM; look for pump presence under hardware monitoring.

  • Pump noise or vibration: A running pump usually makes a faint humming or vibration—touch the unit to confirm.

2. High CPU Temps

  • Pump failure: If the CPU temperature rises quickly after boot, the pump may not be working.

  • Check for air bubbles: Tilt the PC gently to move any air pockets that may be blocking flow.

  • Re-seat cold plate: If recently installed, ensure the AIO cold plate is making full contact with the CPU and thermal paste is applied properly.


RGB/Software Control Issues

  • Missing or frozen RGB effects: Ensure RGB headers are connected correctly (5V/3-pin vs. 12V/4-pin).

  • Sync software: Use the appropriate software for your hardware (ASUS Armoury Crate, MSI Mystic Light, NZXT CAM, etc.).

  • Firmware updates: Some RGB controllers require firmware updates to function properly.


Advanced Diagnostics

  • Test with external fan controller or PSU to isolate motherboard issues.

  • Try AIO on another system if possible.

  • Contact manufacturer support if the device is under warranty and non-functional after all steps.

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