LG Microwave Not Starting – Troubleshooting Guide

Everyone wants a working microwave. Yet, sometimes there are problems. Most people don’t understand how a microwave works so they are left confused with their appliance won’t start. There are a few simple explanations for this problem. 

An LG microwave not starting could be one of three things. It could be a loss of power to the appliance, the child lock is on, or a door switch failure. Other issues, like the magnetron failing, could cause similar problems but wouldn’t cause a total loss of function. 

Those other issues typically would cause a loss of heat or cooking function but not a failure to start at all.

Identifying the Problem 

When someone says their microwave won’t start, there needs to be a few questions beyond that to identify the exact problem. Do you mean the keypad won’t work, the power is completely off or it won’t cook or turn?

Each issue will lead to a different solution. Some of the solutions are easy to fix so you should look to those first before thinking the worst and calling a service technician. 

Keypad Won’t Work

Some people want to use their microwave and find none of the keypad buttons work. They won’t depress. They won’t turn on the microwave. This is frustrating but super easy to fix. 

A non-working keypad on an LG microwave typically means the child lock button is on. LG incorporated a child lock feature as a safety precaution so young children wouldn’t use the appliance unsupervised. 

Sometimes, this feature gets activated accidentally. You can check to see if the child lock button is activated and de-activate it. First, press the stop/clear button. Then, hold down the start/enter button for four seconds. 

At that point, you will either see an “L” pop up on the screen or see it disappear. If it pops up, that means the child lock button wasn’t activated and you just turned it on. A disappearing “L” means it was accidentally activated and you just turned it off. 

Your microwave should now work if you de-activated the child lock feature. 

Read: LG Microwave Not Working But Has Power – Troubleshooting Guide

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What if I activated it?

Those who see the “L” pop up and, therefore, activated the feature can de-activate it by going through the same process again. Press the stop/clear and then hold down the start/enter button for four seconds. Now, the “L” will disappear.

No Power

A microwave that has no power at all with no light and no cooking function likely has either become unplugged or tripped a circuit breaker. 

First, check the back of the machine to make sure it’s plugged in and the cord is properly going into the microwave. Look for damage to the cord or damage where it inserts into the appliance. Now, check your GFIC switch. It is typically a red button on one of your nearby outlets. Press it to reset all your outlets. 

Finally, check the circuit breaker in your electrical box. Sometimes, an appliance will overpower the circuit and that causes it to automatically shut off. Flip the breaker dedicated to your microwave back to on. 

Some circuit breakers look like they are on but really are off because they flipped to the middle of the on/off switch. Be sure to press it on to be sure it is fully in the on position. 

Read: Why LG Microwave Not Heating And Making A Clicking Noise?

My Microwave Isn’t Cooking

Typically, this is what most people mean when they say their microwave isn’t working. A microwave that doesn’t turn on to cook means there is a faulty door switch. 

There are usually three door switches in a microwave. The switches come in contact with the door latch, telling the control panel that the door is closed so it’s okay to start cooking. 

The microwave won’t work when one or more of the switches fail. 

Read: How To Reset LG Microwave?

Can I know if a switch is failing?

There is one distinctive sign that a switch is failing. A microwave that stops in the middle of a cooking cycle means you have the interlock switch is failing. This is the primary switch that controls this function and usually is the bottom switch. 

Door switches for LG microwaves are small black plastic pieces with metal prongs. The prongs usually have three connectors. One is a common connector. The other two are closed and open connectors. 

Testing the Door Switch

Those who are handy and comfortable working on appliances can test the door switches with a multimeter. You take the switch out and put the multimeter prongs on the common and open connectors to see if it has connectivity. Then, you switch the prong on the open connector to the closed connector to double-check your test. 

Working on a microwave can be dangerous if you don’t know what you’re doing. It has a capacitor that will hold up to 5,000 volts of electricity even after the appliance is unplugged. Most advise you to call a service repair tech if your microwave needs a parts replacement. 

Get Genuine Parts

Most also advise getting genuine OEM replacement parts for your LG microwave. There are many after-market parts available but the manufactured replacement part is cheap so there is no reason to buy a generic part. 

These door switches usually cost less than $10 each. 

Read: Why LG Microwave Not Heating Or Turning?

How much will the repair cost?

It depends on your area and the rates of your service technician but door switch replacement takes less than an hour so the average price of this repair is $100. 

Those who can replace the switches themselves will find savings. Replacing the switches is just a matter of opening up the panel, disconnecting the old switches, and reconnecting new ones. 

Is there a reset button on LG microwaves?

No, LG microwaves don’t have a reset button. You must do a hard reset to clear all errors and reset the control panel.

How Do I Reset My Microwave?

You can try resetting your microwave before buying new door switches. Sometimes, a hard reset will correct many problems including loss of power. 

Resetting your microwave is easy. Just unplug it and wait about three minutes before plugging it back in. This will reset the control panel and that could fix any of the relay issues going on with your appliance. 

You will need to test your microwave once you reset it. 

How Do I Test My Microwave?

You can perform a quick test on your microwave by filling a microwavable cup with water. Put it in the microwave for one to two minutes and check to see if the water is hot. It should be boiling so be careful. 

You may have other internal parts problems if the microwave works but the water isn’t hot. 

Are LG microwaves reliable?

LG is one of six known brands considered to be the most reliable for microwaves. It, along with the other five brands, earned an excellent rating in the industry. 

Why did my LG microwave stop working?

A microwave that stops working in mid-cooking tells you something is starting to fail. Typically, it will be the interlock door switch. A microwave that cooks but fails to heat could have a bad diode or magnetron.

How do I find a service tech for my LG microwave?

You can call the LG support center and request a service center near you. They will give you a couple of options. You can call the different ones to find out more about fixing your microwave.

Read: LG Microwave Fan Won’t Turn Off – Troubleshooting Guide

Check Your Warranty Before Repair

You should check first to see if repairs are still covered under the warranty. Look at your warranty to see if the coverage period is still active and if basic parts like door switches are covered. 

Relay this information to the support center representative to see how to apply the warranty to your repair. They should be able to direct you on what paperwork to fill out to get your microwave repaired.

Reader Comments (1)

  1. Hi, hope ypu are doing well.

    My start button on my LG Microwave Model MS4440SR doesn’t work. All other buttons are working and I am able to auto defrost just cant press start if I want do heat up something.


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