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LG Microwave Not Working/Heating

Our microwave is one of those kitchen items we don’t often give much thought to. It’s just there to take care of us but when there are problems, we want to get them fixed quickly.

A common cause for an LG microwave not working is a blown fuse. The microwave’s fuse protects it from power surges, but can blow if there’s an electrical issue. To fix this, locate the fuse, which is typically behind the microwave’s vent grill or control panel, and check if it’s blown. If so, replace it with a new fuse of the same size and rating.

Man adjusting Microwave

There may also be some other issues that need to be corrected with the microwave. Some are easy to fix and others may be more complex.

Before you open the microwave and start working on it, some caution is in order. In most cases, only a trained and qualified repairman should remove any panels in the microwave to repair or replace parts.

Microwave ovens have capacitors that can hold onto power for a long time after the unit has been unplugged. If you come into contact with one of those capacitors, you could be in for a serious shock.

LG Microwave Not Working

We tend to use our microwaves on a daily basis. Without it, our life would be less convenient.

A lack of power is often behind an LG microwave not working. It may have tripped a breaker or the receptacle may no longer be working. Visually inspect the power cable to ensure that it is not damaged.

If the microwave is not working and there is no power to it, there are a few things to check. Any one of these can get the power up and running and restore your LG microwave.

Breaker Panel

Microwaves should be on their own circuit and preferably, on at least a 20 amp breaker. Check the breaker panel to ensure that the breaker has not tripped.

A tripped breaker will be slightly out of line with the other breakers. You may also see some red showing that will indicate the breaker is tripped.

Flip the tripped breaker to the off position and then back over to the on position. If it continues to trip, contact an electrician as it may be a wiring problem or an issue with the breaker.

Power cord

Visually inspect the power cord, paying special attention to the plug. If you notice anything that is burnt looking or if the cord is frayed or cut, it should be replaced.


While you are inspecting the power cord to the microwave, do a visual inspection of the receptacle. If you see any burnt areas on the outside, it would be worth replacing the receptacle.

You could also test the receptacle by plugging in another appliance or perhaps a light. If there is no power to the receptacle on either side or both sides, the receptacle should be replaced.


There are many fail-safes within a microwave that keep it from operating under less than ideal conditions. If a line fuse is blown, it should be replaced.

A line fuse blows when too much current is passing through the microwave. The microwave will not start, although you may have power to the control panel buttons. Test the fuse with a multi-meter for continuity.

Thermal Fuse

The thermal fuse shuts down the microwave if it gets too hot. If the problem is the thermal fuse, the microwave often starts operating after it cools down. If the thermal fuse has gone bad, the microwave will not start.

Thermo protector

The Thermo protector is another failsafe that cuts voltage to the microwave if it overheats. It can be tested with a multimeter.

If the microwave is not working but you do have power to it, you should check for any error codes. If there is an error code, look at your user manual to determine what is wrong.

One other issue that could keep a microwave from working is if the control board goes down. The control board is like the brain or computer of the microwave.

You can’t test a control board but you can visually inspect it. Make sure that you are comfortable opening up the microwave, as it could contain a deadly amount of voltage, even if it is unplugged.

LG Microwave Not Heating

Touching the microwave

If your LG microwave is turning on but it is not heating, it can be a frustrating situation. Here are some things to consider.

When an LG microwave is not heating, a common culprit is a malfunctioning magnetron. The magnetron is the component that generates the microwave’s heating energy. If it fails, the microwave will run but not heat food. Replacing a faulty magnetron typically resolves this issue. However, as this involves handling high-voltage components, it’s recommended to seek professional assistance.

Another potential issue could be with the microwave’s diode. The diode converts the A/C power output of the transformer to D/C, doubling the voltage to nearly 5,000 volts. This high voltage powers the magnetron. If the diode burns out, the microwave won’t heat.

Testing and replacing the diode, which should be done by a professional due to the high voltage, can restore heating functionality.

Faulty door switches can also cause a microwave not to heat. The switches ensure that the microwave only operates when the door is securely closed. If they malfunction, the microwave may run but not activate the heating element.

Inspecting and replacing any broken door switches can solve the problem. This task can be done at home but involves precision to ensure safety and proper function.


These include a high-voltage diode that provides the high-voltage electricity that the magnetron needs to operate.


The magnetron is what cooks the food in the microwave. If it has gone bad, contact a repairman and have it replaced.

Thermal Fuse

The thermal fuse keeps the microwave from overheating. It will automatically cut power if it determines the items are too hot. When a thermal fuse starts to go bad, it may keep the microwave from heating.

Control Board

It may also be possible that the control board has gone bad. You can visually inspect the control board but it is better if you have a repairman take care of the issue.

LG Microwave Not Rotating

Man checking the microwave

A microwave will rotate a glass plate to ensure that any food you are heating is heated evenly. If it is not rotating, it will not operate as efficiently.

A broken coupling or a stripped-out drive coupling is to blame if your microwave turntable is not turning. It may also be a problem with the glass tray support being stripped out or broken.

You can check the drive motor shaft by visually inspecting it. The support for the shaft should pull off easily and then you can inspect the drive motor shaft visually.

If the drive motor shaft or coupling is damaged, they should be replaced. You can also check the turntable motor for continuity if it is not turning at all.

At times, food or debris may get into the drive and block it from turning. Cleaning the food or debris may help to get it turning again and will keep the drive from failing.

Other issues can included the control board, or something as simple as the plate and support not being lined up properly.

LG Microwave Exhaust Fan Not Working

Man adjusting Microwave

If the exhaust fan is not operating properly, the microwave will not work efficiently. This is usually an easy fix.

Copyright protected content owner: and was initially posted on October 9, 2021.

Unplug the microwave and attempt to spin the fan blades manually. If you cannot move the fan blades, the fan motor should be replaced. A defective thermostat may also keep the microwave from turning on the fan.

The thermostat tells the microwave when the fan should be turned on and off. It does so by measuring the temperature inside the microwave cabinet.

If the thermostat is giving a faulty reading, the fan will not kick on to cool things off.

If the fan is working manually but is still not turning, you can also replace the control board. Never do any work on a microwave control board on your own. The risk of electric shock is high.

LG Microwave Fan Won’t Turn Off

Woman holding the window of the microwave

Another issue that can happen to an LG microwave is for the fan not to turn off. This can be a frustrating and potentially dangerous problem.

When the thermostat is not sending the proper temperature to the control panel, the fan will continually run. The fan kicks on automatically when the temperature in the cabinet gets too high. Until the thermostat reads the control panel is cooler, the fan will continue to run.

Open the door of the microwave to see if the fan turns off. If the fan continues to run, close the door quickly. You should never operate a microwave oven with the door open.

The switch is in the door may also be bad in this instance. It could be more than one problem that is leading to the issue of the fan running continually.

If you are cooking something on the stove, such as boiling pasta, the steam may go up and increase the temperature inside of the microwave, triggering the fan to start. Once it cools down, the fan should turn off.

Can this be fixed?

Copyright article owner is for this article. This post was first published on October 9, 2021.

It may seem like an unusual way to fix a microwave, but some tech support representatives have told homeowners to open the microwave door and slam it shut 10 times.

The homeowners reported that it worked well. Some thought that it may reset the microwave but others think it just jarred something loose that shouldn’t have been stuck.

If the fan is continually running and not turning off, it may be best to unplug the microwave or turn it off at the circuit breaker. In fact, resetting the microwave may just be the fix that it needs.

You can reset a microwave in the same way that you reset most major appliances. Turn off the power to the microwave for 60 seconds and then turn it back on. If it didn’t work, try leaving the power off overnight.

LG Microwave Keeps Turning Off

Woman putting food inside the microwave

If your LG microwave is continually turning off, it can be a very frustrating problem. There are a few different issues that can cause this problem.

A faulty door switch will cause the microwave to turn off and back on. The door switch signals that the door is either open or closed. If it is closed, the microwave will run. If it is open, it will shut off automatically. If the door switch is faulty, it may turn off multiple times.

A door switch is a relatively easy thing to fix since you are not close to a capacitor. You should be cautious fixing anything with a microwave, especially if you’re going to be in where a capacitor could shock you. Capacitors hold onto voltage long after the microwave has been turned off.

You can also try pulling on the door and seeing if it opens easier than it should. If the door latch is not operating properly, then the pressure from inside the microwave may be pushing it out and causing it to open slightly.

If there is a power fluctuation of any type, it could also cause the microwave to turn off. This could include an overall power failure, but it may also be associated with issues in the breaker panel, with the receptacle, or even a damaged power cable.

If an internal component that protects the microwave from overheating malfunctions, it may also shut off intermittently. These include the thermostat, Thermoprotector, and other items that measure the temperature inside the microwave.

As those parts go bad, they can intermittently shut off the microwave. They may allow the microwave to start again, but it will be temporary.

LG Microwave Does Not Start

Man looking at the microwave

When your LG microwave does not start, it will be a very inconvenient problem. Fortunately, the solution is often easier than most people think.

An issue with the circuit breaker or outlet is often to blame when the microwave will not start. You may also want to visually inspect the power cable to make sure it is not damaged. Do not run any other appliances on the same circuit as a microwave.

Resetting the microwave often help it to start again. Turn the power off at the circuit breaker or unplug the microwave for at least 60 seconds. After plugging it back in, test to see if it will start.

Since the capacitors in the microwave can hold onto voltage for a long time after it is unplugged, you may need to unplug it for a longer amount of time. Generally speaking, it may take up to 24 hours for the capacitor to be at a safe level.

Try unplugging the microwave and leaving it unplugged overnight. If it doesn’t start after you restore the power, you may need to contact a repairman.

LG Microwave Light Not Working

Man fixing the microwave

It often helps to shed some light on the subject when we are cooking food in our microwave. If the light is not working, the fix is usually easier than most people realize.

Microwave lights can be replaced. You can order a new light that is specific to your microwave and swap it out, just as you would change the bulb in an oven or in a lamp.

If you are still having a problem with your LG microwave light not working, make sure that you have power to the unit. If you have power, then it may be an issue with the light socket.

You can test the light socket for continuity using a multi-meter. It can be replaced fairly easily.

ReadyToDIY is the owner of this article. This post was published on October 9, 2021.

When your LG microwave is not working, check the power first. It could be a problem with a breaker, the receptacle, or even the power cable. Always run your LG microwave on its own circuit with at least a 20 amp breaker.