Troubleshooting MIG Welders

MIG (which stands for metal insert gas) welders use electricity to create high temperatures to meld two pieces of metal together.


It is easier to strike and arc when using a MIG welder than with a stick welder. MIG welders push the oxygen out of the way by forming a shield of carbon and argon around the weld. If you find you are experiencing problems with your MIG welder, try troubleshooting the issues on your own before calling in a professional.

If the torch on your MIG welder will not light, but the "machine on" LED light is lit, first check the "safety" LED. If it is lit, press the "safety reset" button. Also, check the air supply to the unit. The machine cannot start without any air flow. Low air pressure will also cause it to not start. Set your machine to purge mode to turn on the air. The regulator needs to be set to a minimum of 60 psi. Raise the pressure slowly until the "air pressure" LED lights. If it still does not light at 75 psi, you must have a leak or clogged air filters.


If you cannot establish an arc with your MIG welder, even with the air flowing and the "output on" LED lights being lit, check to make sure the torch consumables are in tightly and not dirty or greasy. Also, check that there is a high frequency at the spark gap and that the CR2 engages. You may want to blow compressed air on all the upper compartments. If your arc starts but sputters, ensure the air supply is not being compromised by oil or a great deal of water. If there is either, you will need to filter the air or switch to nitrogen or bottled air.

LED Lights

If the "thermal" LED light is lit and the "fault" LED is blinking, it means the machine is overheated. You should let it cool and then reset it. Don't allow the air intakes to become blocked. If your "air" and "fault" LED lights are alternating, you need to replace the control PC board. If the "output on" and "fault" LEDs blink alternatively, the pilot arc duty cycle has been exceeded. Your machine will cool down and the lights will stop flashing in approximately 20 seconds.

About the Author

Kelly Seiler has been a freelance writer and editor in Texas for the past 10 years. She grades essays on national standardized tests and writes reports on service received at local restaurants and businesses. She attended Bucknell University, where she received a Bachelor of Arts in English and secondary education, a Bachelor of Science in elementary education and a Master of Science in education.