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Why Is Hotend Not Heating? How To Fix?

If your hotend isn't even getting warm during your print, diagnosing the issue can be very confusing and frustrating. Still, repairing the problem can be simple if you know what causes a hotend to fail. 

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Hotends are complicated 3D printer components, and every little part inside the hotend is invaluable to the printing process. However, if your hotend isn’t even getting warm during your print, diagnosing the issue can be very confusing and frustrating. Still, repairing the problem can be simple if you know what causes a hotend to fail. 

If your hotend is not heating, it might have an issue with the thermistor, wiring, or heat cartridge. These issues affect how hot your printer will get, and fixing them may be as simple as tightening some wires or as complex as replacing the heat cartridge or thermistor.  

In this article, I’ll discuss some of the common reasons why your hotend might not be heating and tell you a solution that may be able to fix your issue—hopefully making your day that little bit easier. Let’s get started.

1. Problems With the Thermistor

Understanding that your hotend is one of the essential parts of your 3D printer can help you comprehend the size of the issue. 

The hotend controls filament extrusion, and your machine would be useless without it. Inside this component, you’ll find several parts that regulate the hotend’s temperature and the filament’s tension as it moves out of the nozzle. 

One of the most critical parts inside the hotend that manages temperature is the thermistor. A thermistor (like a thermostat) reads the machine’s temperature and controls the heating element to keep your printer’s heat constant. 

If the thermistor isn’t working correctly, it may stop the hotend from releasing the filament due to the temperature being too high or too low. If you find that your thermistor is recording inaccurate temperatures and that the hotend only gets warm, you may need to replace it. 

How To Fix

Turning on your printer is the initial step in this procedure. Verify that it’s turning on and functioning correctly. Then, start a preheat cycle. 

After it’s finished, you must check and read the temperature. Firstly, observe your printer’s digital temperature reading. If the printer indicates that the hotend is up to the preheat temperature, the thermistor senses some heat. However, if the measurement does not change, the thermistor might not be the problem. 

Next, check the temperature of your nozzle to determine if the hotend is warmer than usual using a thermometer. I use a meat thermometer since these are suitable for measuring high temperatures. Place the thermometer on the nozzle and wait for a few minutes to see how hot the hotend is. 

If the temperature is close to room temperature, or if the temperature reading on your printer’s screen is inaccurate, you’ll know the thermistor isn’t working correctly.

Before you call customer service, check to ensure that you have plugged the thermistor in. If you never secured it or it came loose, you must use a screwdriver to remove the printer’s rear panel and check the connection. 

However, if the connection seems secure, you should now get in touch with the maker of your 3D printer to get more information. Since this is a critical issue, they’ll be able to offer guidance on how to fix it. 

2. Wiring Issues

Correct wiring can play a massive role in the functioning of your 3D printer. If the wiring is incorrect or loose, you will surely experience some issues, one of which is a malfunctioning hotend. 

To see if the wiring is causing the malfunction, you should check inside the 3D printer where all the wires are plugged in. Look out for broken, disconnected, or misplaced wires. If you find such a thing, continue onto the how to fix section.

How To Fix

You must remove the bottom cover of your 3D printer to address the wire problem. Your device’s mainboard, essentially its brain, may be found within.

Examine the wires closely to make sure that everything is plugged in correctly. You can use your printer’s manual or assembly guide to check everything. If you find anything in the incorrect place, all you need to do is plug it in where they go.

Plug any loose wires a little more firmly if necessary. You should contact the company that made this printer if any cables are damaged.

Be cautious when working with the wires, and unplug your printer before opening it up. You don’t want to get electrocuted while fiddling with your printer. 

3. Something Has Gone Wrong With the Heater Cartridge

The heater cartridge is the metal tube that heats your hotend. This small part is in charge of all the thermal energy that liquefies your filament, so if your printer’s temperature is inaccurate or too low, there could be something wrong with the cartridge. 

In most cases, if the cartridge is at fault for your issue, the printer just won’t warm up. Your printer’s live temperature reading will be accurate, but it will stay at room temperature or slightly hotter. The hotend will not get up to the desired temperature. 

If that scenario describes the issue with your 3D printer, keep reading to learn how to fix it. 

How To Fix

The cartridge heater should be changed for a new one as this will solve the problem the best. 

I recommend you speak with the printer manufacturer and inform them of the issue with the damaged cartridge heater as soon as you notice it. If your printer is still under warranty, the company may send you a replacement part free of charge. However, if not, you will need to get a new one yourself. 

In cases where finding a replacement is necessary, you must be sure to get the correct part. Each printer requires a specific heater cartridge with a particular size and power. Mismatching this part could result in more issues. 

Your 3D printer should be ready to use after installing the new cartridge heater. Just make sure to test it out so you can determine whether it works properly or not.


If your hotend isn’t warm, you may have a faulty thermistor, loose or damaged wires, or a malfunctioning heat cartridge. 

These parts play an integral role in how your hotend regulates its temperature, but fixing them shouldn’t be too difficult. To start, test your thermistor, then check the wiring inside your printer. If these tests do not resolve the issue, you may have to replace the heater cartridge.

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About Ben

I started 3D printing since 2013 and have learned a lot since then. Because of this I want to share my knowledge of what I have learned in the past years with the community. Currently I own 2 Bambulab X1 Carbon, Prusa SL1S and a Prusa MK3S+. Hope you learn something from my blog after my years of experience in 3D printing.