How to Fix Cooling or Hotend Fan Not Working – Ender 3 & More (2024)

To successfully print 3D models, having proper cooling is crucial. Sometimes some users face issues with their 3D printer cooling or hotend fans not working, so I decided to write an article detailing how to fix this problem.

To fix cooling or hotend fans not working, clean the fan blades and ensure that the fan cables are not cut or disconnected. Calibrate the slicer cooling settings and correct the G-Code M106 command. Aside from this, ensure that correct voltages are being supplied to the fans. If the fan is dead, a replacement will be the only solution.

Keep reading to learn the detailed solutions and related information that will be important to fix your 3D printer’s cooling or hotend fans.

How to Fix 3D Printer Hotend Fan Not Working

Here’s how to fix the 3D printer hotend fan not working:

1. Clean fan blades
2. Fix fan wires
3. Check the fan jack on the motherboard
4. Correct soldering joints
5. Replace the fan

1. Clean Fan Blades

One efficient method to fix the hotend fan not working is to clean the fan blades and remove obstructions causing blockages. Dust, debris, filament strands, and other foreign particles can build up in the fan blades or the fan housing. This can cause the fan to clog and not spin.

To clean the hotend fan:

1. Turn off the 3D printer and unplug the cord
2. Using the screwdriver, open the fan housing
3. Using pliers, remove filament strands or particles stuck in there
4. Blow the dust out using compressed or canned air

One user recommended turning off the fan and pulling out the stuck filament strands or little wisps using tweezers.

Another user said that you should check and ensure nothing is caught in the fan. Check the blades as they can snap and get stuck in there. In this case, the fan replacement will be the only solution.

One user suggested not to use a vacuum cleaner or blower for cleaning as it can cause static discharge and kill electronic components. It may not do anything to hotend fan but it is better to avoid using such tools to clean the power supply fan or the electronic box fan.

Aside from this, ensure the fan blades don’t spin uncontrollably while blowing air as it can cause the motor, controller board, or PSU to fail.

Here is a video on how to clean fans with additional information on clearing a clog and changing the nozzle.

2. Fix Fan Wires

Another way to fix the hotend fan not operating is to repair any cut, damaged, loose, or disconnected fan cable. As fans require only 12-24V to operate, the wires are thin and can be damaged because of constant movement or a pull.

One user said that his Ender 3 printer fan was randomly turning ON and OFF. A slightly cut wire was the actual cause that he found out by moving the wire and realizing that the fan would go ON and OFF with the movement. Reconnecting or fixing the wire wasn’t a big deal and it solved the problem as well.

Here is a video detailing different DIY methods to fix broken wires.

To prevent this from happening, you can use some stain relief or ties on your wires to keep them in a good position. This will reduce the chances of wires breaking off because of constant movement.

Some good products that you can buy from Amazon include Zip Ties and Spiral Wraps. You may also use a Drag Chain from Thingiverse for major wires.

3. Check Fan Jack on Motherboard

One method that works for the hotend fan not working is checking their connection and making sure it is plugged into the correct jack on the motherboard.

One user said that you can verify this by turning on the 3D printer without heating it. Go through the Main Menu > Control > Temperature > Fan, increase the fan speed to 255, and press the knob.

If the hotend fan starts spinning after this procedure, the hotend fan is plugged into the part cooling fan on the motherboard.

Other users recommended tracking the fan wire into the mainboard after unplugging the power and opening the control box. Here is an image of the 3D printer mainboard labeling different ports and connections.

Swap the fans by connecting them to the “Add Fan” port on the board and test it using the knob as stated earlier.

For safety, the user recommended unplugging the power from the control box first and then turning the power switch on. This will discharge all the power from the control box making it safe for you to poke. Turning the power switch off is essential while plugging it back in.

You can check out this Reddit post with an image of Ender 3 labeled mainboard and a detailed discussion on installing a 12V fan.

4. Correct Soldering Joints

Another good way to fix a hotend fan not working is to check the welds or soldering joints on the fan plate and fix them using tin. Incorrect soldering can lead to loose or broken connections. This will cause the fan to turn ON and OFF during the printing process or not work at all.

For soldering wires, connections, or joints on circuits, you will need tools like a soldering iron station, solder iron tip, and solder. You can get all-in-one by buying an X-Tronic Model 3020-XTS LED Soldering Station from Amazon.

One user said that fans can stop working if a soldering point becomes too hot and gets damaged a bit. You can verify this by removing the label on the inner side of the fan and looking for any broken soldering points.

Here is a basic video on how to do soldering of different types using tin.

5. Replace the Fan

The most common method to fix the hotend fan not working is to replace it with a new one. This is not that difficult as they are cheap and easy to install. If everything is fine and it is still not working, the fan is most probably dead and needs replacement.

One user recommended Noctua NF-A4x 10 FLX, 3 Pin, 40x10mm fan which you can buy from Amazon. It is easy to install as it requires scissors and pliers to install if it does.The user said that he is using it for 2 months now without any clogging issues from heat creep and the noise level is 17.9db which is also less than many other fans.

Check out the video below to see how to properly replace the hotend fan on Ender 3 and more.

How to Fix 3D Printer Cooling Fan Not Working

Here’s how to fix the 3D printer cooling fan not working:

1. Enable print cooling from the slicer
2. Blow compressed air
3. Check the fan voltage
4. Increase fan speed
5. Verify the M106 command in G-Code

1. Enable Print Cooling from Slicer

To fix the cooling fan not working, ensure that “Enable Print Cooling” is checked under the “Cooling” settings in Cura. These settings can automatically be enabled or disabled in your slicer depending on the material you are using.

If you unchecked this setting while printing a filament that didn’t need cooling and forgot to turn it back ON, this could be the reason why the cooling fan is not working.

2. Blow Compressed Air

One way to fix the cooling fan not working is by blowing compressed air through the fan blades and housing. This can blow out the dust while removing most of the filament strands and wisps as well.

One user said that his cooling fan stopped working and he blew some compressed air through it. This idea worked fine and the fan hasn’t stopped since then.

Another said that blowing air can sometimes generate voltage damaging the mainboard. To avoid this, first, remove the cooling fan connector from the board or unplug the 3D printer.

One user suggested making sure that you don’t spray on the print surface. Sometimes, liquid drops come out that can affect the bed adhesion.

Something like the Falcon Dust-Off Compressed Gas Duster from Amazon would work for this.

3. Check the Fan Voltage

Another method to fix cooling not working is to check the fan voltage using a multimeter. If the voltage is not stable or as required, replace the cooling fan as it is broken.

One user said that if all slicer settings are fine:

1. Disconnect the fan connector
2. Check the fan voltage in the plug using a multimeter

If the voltage is 24V DC at 100%, you may check the solder points’ voltage next. This can be done as follows:

1. Reconnect the connector to the fan
2. Remove the housing from the fan by removing the two screws
3. Unscrew the fan from the fan shroud/housing by removing its 4 screws
4. Peel off the label at the back side of the fan
5. Place test lead pins on solder points and check voltage using a multimeter

If everything is fine, the fan is dead and needs replacement.

You can buy any multimeter such as Etekcity Digital Multimeter from Amazon.

Take a look at the video below on how to test a cooling fan and check voltage using a multimeter. Though the video is for a computer cooling fan, the process will be the same for 3D printer fans as well.

4. Increase Fan Speed

Another way of pushing your cooling fans to work is by increasing their speed. The fan does not start if the speed is at 0% or sometimes needs a slight nudge even at 30%. You may tweak “Initial Fan Speed” as well but just for testing the fan because too much cooling can affect first-layer adhesion.

Different levels of speed are recommended for different printing materials such as:

• ABS: 30%
• TPU: 40%
• PETG: 50%
• PLA: 100%

These speeds can vary depending on different conditions and printing projects.

Another user said that you can check and set the fan speed on a 3D printer as:

• Main Menu > Control > Temperature > Fan Speed > 100 (recommended for testing the fan) > Enter (by using the rotating knob down)

5. Verify M106 Command in G-Code

Another way to fix a cooling fan not working is by checking the G-Code M106 command and ensuring it is running. M106 is the command that controls or instructs your 3D printer cooling fan and incorrect values can cause the fan to stop.

To check and ensure that G-Code is fine:

• Export the file and slice the model.

• Save the G-Code file and open it with Notepad, Notepad++, or MS Word.

• Search “M106 P0 S255” and ensure that it is in the same syntax.

P0 indicates that the fan is connected to the “Extruder 1” which is the default value of Ender 3 or any other 3D printer with a single extruder. M106 command with P1 will cause the fan to stop. In Ultimaker Cura, you can check fan number by:

• Go to Menu Bar and Click Settings > Printer > Manage Printers

• Click Printers and open Machine Settings

• Click Extruder 1 and locate the Cooling Fan Number

S255 indicates that the fan will be running at 100% speed, it ranges between 0-255 for 0-100%.

One user said that the cooling fan doesn’t work on the first few layers, sometimes at low speed such as 33%, and may need a slight push. For that reason, set the speed at S255 (100%), at least for testing the fan.

Another user said, simply open the G-Code in Notepad, type the command M106 S255, and save the file with the “.gcode” extension instead of “.txt”. Run the file after uploading it to SD Card and the fan should start operating.