How to fix an LG microwave that’s not cycling properly

When your microwave suddenly stops working the way it should, it can be frustrating—especially when you rely on it to reheat leftovers or quickly make a meal. If your LG® microwave is running but not cycling properly, don’t worry. The problem may be easier to fix than you think.

At Asurion, our experts help millions of people take care of their devices and appliances every day. If your microwave isn’t cycling, we’re here to help. Here’s what could be causing the issue and how to fix it.

What does it mean when your microwave isn't cycling?

Microwaves cycle their power on and off to control heat and cook food evenly. If yours is not cycling properly, it may stay on too long, turn off too soon, or not heat at all. This can result in cold food, uneven cooking, or a microwave that shuts down unexpectedly.

If your microwave is running but not heating, check out our guide on why your microwave turns on but doesn’t heat.

Common reasons your LG microwave isn’t cycling properly—and how to fix it

1. The door isn’t closing all the way

Microwaves won’t run if the door isn't securely shut. Even a small misalignment can prevent it from cycling.

What to do:

• Open and firmly close the door.
• Check the door hinges and latch for damage or food debris.
• Clean the door seal with a soft cloth and warm, soapy water.
• If the door still doesn’t close properly, it may need repair from a technician.

2. The power settings are too low

If your microwave is set to a low power level, it may seem like it’s not cycling or heating correctly.

What to do:

• Check your power level settings.
• Increase the power to high and test again by heating a cup of water for one minute.
• If it heats normally, the issue may have been your settings.

3. The microwave is overheating

When a microwave gets too hot, it can shut down or stop cycling to protect its internal parts.

What to do:

• Unplug the microwave and let it cool for 30 minutes.
• Make sure vents are not blocked.
• Avoid running the microwave for long periods without breaks.
• If your microwave repeatedly overheats or shuts down, it may be reaching the end of its lifespan. Read more about how long microwaves usually last.

4. The magnetron isn’t working

The magnetron is what produces heat inside your microwave. If it fails, your appliance may run but not heat or cycle correctly.

What to do:

• If your microwave is not heating food at all, this could be the issue.
• This repair involves high-voltage parts, so it’s best left to a professional.
• For more tips, check out our guide on what to do if your microwave isn’t heating.

5. There’s a problem with the control board

The control board manages the microwave’s functions. If it malfunctions, it can cause cycling issues.

What to do:

• Try unplugging your microwave for 1–2 minutes to reset it.
• Plug it back in and test it again.
• If the issue continues, the control board may need to be repaired or replaced.

When to call in an expert

If none of these steps solve the problem, it’s time to get help. Microwaves contain high-voltage parts that can be dangerous to fix on your own. A certified repair technician can safely diagnose and repair the issue—often on the same day.

FAQ

What does it mean if my LG microwave runs but doesn't heat?

This often points to a failed magnetron, diode, or capacitor. These parts are responsible for generating heat and may need professional repair.

Is it safe to use a microwave that isn’t cycling properly?

If your microwave is not heating food or shuts off unexpectedly, it’s best to stop using it and have it checked by a professional. Continued use could lead to more damage.

How do I reset my LG microwave?

Unplug it for about one to two minutes, then plug it back in. This can clear minor software issues and restore normal operation.

Can I replace the magnetron in my LG microwave myself?

It’s not recommended. The magnetron and other internal parts carry high voltage even after unplugging the microwave. Always contact a repair expert for help.