Why Won’t My Microwave Heat Up? (5 Solutions!)

Microwaves, oven, cabinet However, when your microwave oven suddenly stops heating up, it can throw a wrench into your plans. From checking the internal components to inspecting for rust or low resistance in the crucial parts – tube, heating issue, oven, new microwave – we’ve got you covered. Whether it’s the fan, tube, or oven that needs attention after years of use, we’ll guide you through the process. So if you’re scratching your head wondering why your trusty microwave oven isn’t doing its job anymore, fret not – we’ve got the inside scoop on getting it back up and running.

Is your Frigidaire microwave oven not heating your food, and you can’t see why and are planning to call the pros? Don’t just tube yet – at least not before considering the reasons oven I’ll share shortly. 

Generally, a Frigidaire microwave oven won’t heat due to lack of power, locked control panel, unlatched door, wrong setting, or faulty component, especially the magnetron, diode, capacitor, transformer, Thermoprotector, control board. 

So, it’s best to go through those oven checks before calling an expert. Who knows, you could fix the microwave and oven DIY and save on repair costs. 

Remember, a Frigidaire oven and microwave that won’t warm your food is as good as a non-working microwave. You can’t use the oven, and that’s why you should try and troubleshoot it as soon as you can. 

Of course, the troubleshooting starts with first identifying why the microwave oven behaves that way. Then you should find its fix, which I’ll share in this guide. 

Here we go!

Frigidaire microwave not heating

In a rush? See the Frigidaire microwave troubleshooting guide for a non-heating microwave below. 

Quick Troubleshooting Guide for a Frigidaire Microwave Not Heating

  Possible Reason Recommended Fix
1. Lack of Power Ensure your microwave has power
2. Locked Control Panel Disable safety/child lock to unlock the control panel
3. Unlatched Door Remove any door obstruction, and if the door switch is defective, replace it
4. Wrong Setting (wrong power level or timer setting) Adjust the power level and timer accordingly
5. Faulty Component Have an expert replace the magnetron, diode, high-voltage capacitor, transformer, Thermoprotector, or control board if faulty

Why Is My Frigidaire Microwave Not Heating Up?

Essentially, there are five explanations for a Frigidaire microwave that won’t heat. They include the following

1. Lack of Power 

Without power, your Frigidaire microwave cannot heat up. It needs a good electricity supply to get hot and warm your food. For that reason, you’ve to ensure it has power, and if it doesn’t, the issue could be any of these:

  • Power outage – If there is an outage, which you can tell from the main meter and other appliances, your microwave won’t start and heat up. That doesn’t mean, however, that your microwave has a problem, and that’s why this should be the first check to avoid unnecessary concern.

  • Tripped breaker – A power surge often trips the breaker to protect the microwave. Once that happens, the microwave’s power supply is cut off, which means the microwave won’t start until you reset the breaker.

  • Unplugged, defective, or wrong power cord – A Frigidaire microwave requires a 120V 3-prong power cord. What’s more, the cable should be firmly plugged in and working. If that’s not the case, the microwave won’t get hot.

  • Bad fuse – Another victim of a power surge is the thermal fuse. If there is a surge, the fuse may blow up, and when it does, it cuts off the microwave’s power supply, preventing the microwave from starting and getting hot.

  • Defective outlet – The power cord may be working, but if you plug it into a faulty wall socket, the microwave won’t start.


Your microwave must have the power to work. So, check if there’s an outage. If there is, then you don’t have to do anything but wait. But if there’s no outage, check the breaker for tripping and reset it if it’s off.

Then use a multimeter, preferably a digital version, to test the power cord, thermal fuse, and power outlet for continuity. If any of the three shows no electrical continuity, it’s faulty. So, you’ve to replace it.

Meanwhile, ensure the power cord is firmly plugged into the wall outlet and is the right type (120v 3-prong).

2. Locked Control Panel

Frigidaire microwaves typically have the Child/Control Lock, or Safety Lock, to stop children from operating them. Since this feature locks the control panel, the microwave can’t run. And as a result, it won’t get hot.

If the lock feature is on, it eliminates any other concern.


Disable the Control Lock feature to unlock the control panel. You can do that by long-pressing the button on the control panel until it disappears from the display.

3. Unlatched Door

A Frigidaire microwave won’t start if its door is not shut. Overall, two issues could stop the door from closing, and they are:

  • An obstruction – The obstruction could be an oversized plate or shipping spacers. So, check both issues.

  • A faulty door switch – If the door switch is broken, it won’t work, and that stops your microwave door from shutting all the way.


Check if the plate is too big for the microwave. If it is, replace it with the correct plate size. Then check if there are any shipping spacers blocking the door and remove them.

And if the issue is not an obstruction, test the door switch for electrical continuity using a multimeter. If the button shows no electrical continuity, replace it. 

Why is my Frigidaire microwave not heating up

4. Wrong Setting

You must pick the right setting for your microwave to work. Sometimes you may unintentionally misadjust the power level or timer setting, which could prevent the microwave from warming up.

Therefore, check the power level and timer setting to ensure they are correct. You may need your manual here.


Adjust the power level and timer setting according to the product manual.

5. Faulty Microwave Component

Several components could prevent the microwave from heating if they fail. That includes the magnetron, high-voltage capacitor, diode, high-voltage transformer, Thermoprotector, and control board.

If the magnetron, for example, is defective, the microwave will fail to generate enough microwave frequency to heat your food. If the high-voltage capacitor or diode fails, the microwave will fail to convert AC into DC.

On the other hand, a blown-up Thermoprotector cuts off the microwave’s power supply when the microwave overheats, while a defective high-voltage transformer fails to store the high-voltage.

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And if it’s none of the five microwave components, it could be the control board. The microwave fails to start and heat up if the main control board is defective.


If any of the six mentioned microwave components is faulty, the microwave won’t heat. But given that a microwave can still produce some high voltage even when plugged out, replacing any of those parts is not recommended. So, call an expert here.

New Frigidaire Microwave Not Heating

If your non-heating Frigidaire microwave isn’t heating, rarely does that happen due to a failed component. In most cases, the issue is a lack of power. So, start by checking if the microwave has power using the tips I shared earlier.

If the problem is not power, check the door to ensure nothing stops it from shutting all the way. Then check the control panel to see if the Child/Safety Lock functionality is active and disable it.

If the microwave doesn’t heat after that, call an expert if you’ve used it, but if it’s the first time to use it, take it back to the seller.

Frigidaire Microwave Timer Works But Not Heating

While you expect the Frigidaire microwave to get hot when the timer works, sometimes it won’t. That’s likely due to a blown-up magnetron failing to generate the needed frequency to heat your food.

If the magnetron is okay, then the door switch could be defective. You can tell a faulty switch if the door won’t shut even though nothing obstructs it.

Another way to check for a defective door switch is to test it for continuity, whereby the lack of continuity confirms it’s faulty.

new Frigidaire microwave not heating

Frigidaire Microwave Not Working After Power Outage

A Frigidaire microwave won’t work because of a power outage. So, you expect the appliance to run once the power is restored.

What if it doesn’t? Then consider resetting it by flipping off the breaker for 3 minutes or so and then start the microwave. You can also unplug the microwave for 3 minutes to reset it.

But if the microwave won’t work after a reset, check if the door is closing and ensure the microwave has power.

People Also Ask

1. Does a Frigidaire Microwave Have a Reset Button?

Sadly, Frigidaire microwaves don’t have a designated reset button. You, however, can reset them by flipping the breaker off for 3 minutes, then on, or by unplugging the microwave (for 3 minutes).

2. How Do I Reset My Frigidaire Microwave?

You can reset a Frigidaire microwave by cutting off its power supply for at least 3 minutes. The first option is to flip off the breaker and then on, and the second option is to plug it out for 3 minutes.

3. What Is the Cause of Microwave Not Heating?

A microwave won’t heat if it doesn’t have power. So, you must check for a power outage, a non-working outlet or power cord, a blown-up fuse, or a tripped breaker.

If the microwave has power but won’t heat, check if the power level and timer setting are correct and unlock the control panel if the Child/Safety/Control Lock function is on.

The other cause could be a non-latched door or a faulty component such as the magnetron, capacitor, diode, Thermoprotector, or high-voltage transformer.

4. Why Is My Microwave Running But Not Heating?

Your microwave is running but not heating because the high-voltage magnetron is defective. In such a case, the magnetron fails to generate the needed frequency for heating your food. It could also be that the door is not shut correctly. So, check it and remove any shipping spacers or any other obstructions.

5. How Do You Fix a Microwave That’s Not Heating?

You can fix a microwave that’s not heating by:

  • Ensuring the microwave has power

  • Disabling the control panel if it’s locked

  • Selecting the correct power level and timer setting

  • Properly closing the microwave door – removing any obstructions

  • Replacing any faulty component (magnetron, Thermoprotector, diode, capacitor, high-voltage transformer, or control board)

How do I find a replacement magnetron for my microwave?

To find a suitable replacement magnetron for your microwave, you will need to consider the following steps:

1. Determine the make and model of your microwave: Take note of the brand and model name or number of your microwave. This information is usually found on a label or sticker located on the back, side, or inside the microwave.

2. Research compatible microwave brands: Look into the various brands that manufacture magnetrons compatible with your microwave model. Popular brands include LG, Panasonic, Samsung, and others. Ensure you focus your search on brands known to produce magnetrons that fit your particular microwave type.

3. Identify the model number: Once you have determined the brand, make sure to find the model number of the magnetron that matches your microwave. This information is usually found on a sticker attached to the magnetron itself.

4. Seek reliable suppliers: Look for reputable suppliers or authorized retailers that carry replacement magnetrons. This can be done by visiting local appliance stores, contacting the microwave manufacturer directly, or searching for online retailers specializing in microwave replacement parts.

5. Verify compatibility: When selecting a replacement magnetron, ensure that it has the same model number as the original one. This step is crucial to guarantee compatibility and proper functionality of the magnetron with your microwave. Double-check the specifications and descriptions provided by the supplier to ensure an accurate match.

6. Purchase and installation: Once you have found a suitable replacement magnetron, proceed with the purchase. Follow the supplier’s instructions on how to correctly install the magnetron in your microwave. If you are uncertain about the installation process, it is recommended to seek assistance from a professional technician or refer to the microwave’s user manual.

By following these steps, you should be able to find and acquire the correct replacement magnetron for your microwave, ensuring its compatibility and continued reliable operation.

Closing Thought:

Above is a guide to use on a Frigidaire microwave not heating. It should be handy when you want to save on expert repair costs. And as seen, other than the failed components, the other four issues are DIY. You can handle them yourselves and save up. But as for the failed components, seek an expert’s help since the procedures are technical and dangerous.

Understanding Microwave Heating Issues

When your microwave won’t heat up, it can be frustrating. But before panicking, there are a few troubleshooting tips you can try. First, check if the power cord is securely plugged into the outlet. Sometimes, a loose connection may prevent the microwave from heating properly.

Another important step is to ensure that the microwave door is closed properly. If the door isn’t fully closed or has any damage, it can interfere with the microwave’s ability to heat food effectively.

Lastly, make sure that the timer and cooking settings are correctly set. Incorrect timer or power level settings might lead to ineffective heating of food items in the microwave.

These simple troubleshooting steps can often resolve minor issues causing your microwave not to heat up properly.

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Microwave Component Failures

Magnetron Issues

The magnetron is a crucial component responsible for generating the heat necessary to cook or reheat food in a microwave. When it starts failing, you might notice that the control panel buttons don’t respond as they should. The display screen may show incorrect information or not function at all. Another sign of magnetron failure is the inability to adjust cooking settings or timer.

If your microwave exhibits these signs, it’s likely that the magnetron needs replacement. A faulty magnetron can result in no heat being produced or uneven heating of food inside the microwave. To address this issue, seeking professional assistance is essential as replacing a magnetron requires expertise and knowledge.

High Voltage Diode Problems

The high voltage diode plays a crucial role in converting high voltage AC power into DC power for the magnetron to produce heat within the microwave. Signs of diode failure include no heat being generated when using the appliance and even sparking inside while operating.

In case you observe any of these symptoms, consulting with a professional technician becomes imperative. Replacing a faulty diode demands precision and understanding of electrical components beyond typical user capabilities.

Door Switch Malfunctions

A critical safety feature in microwaves, the door switch ensures that the appliance only operates when its door is securely closed. If there are issues with this component, you may find your microwave not starting at all or stopping mid-cycle unexpectedly.

When facing problems related to door switch malfunctions, it’s advisable to seek help from an experienced professional who can accurately diagnose and replace this part if needed.

Fixing a Non-Heating Microwave

When your microwave won’t heat up, the first thing to check is the power supply. Test if there’s electricity running to the microwave outlet by plugging in another appliance. If it works, then you need to reset any tripped circuit breakers or replace blown fuses. Without proper power supply, your microwave won’t be able to function.

Resetting a tripped circuit breaker or replacing a blown fuse can solve the issue of a non-heating microwave. These simple steps ensure that your microwave has access to the necessary power it needs for heating food effectively.

  • Check if there is power supply to the microwave outlet.

  • Test the outlet with another appliance to confirm functionality.

  • Reset any tripped circuit breakers or replace blown fuses if necessary.

Investigating Intermittent Operation

Starts and Stops

Microwave ovens that start and stop intermittently during use can be frustrating. One possible cause for this issue could be faulty door switches or overheating problems. These components play a crucial role in ensuring the microwave operates safely. If you’re experiencing this problem, it’s crucial to consult a professional technician for an accurate diagnosis and repair.

Another common reason for intermittent operation is overheating. When the internal temperature of the microwave rises too high, it triggers a safety feature that shuts off the appliance temporarily to prevent damage or fire hazards. This can occur due to issues with the cooling fan, ventilation, or faulty thermal cutoffs.

If your microwave is exhibiting these symptoms, it’s essential to address them promptly to avoid potential safety risks and ensure uninterrupted functionality.

Sparking Causes

Sparks inside a microwave are not only concerning but also dangerous. They typically indicate a problem within the appliance that needs immediate attention. Common causes of sparking include presence of metal objects, damaged waveguide cover, or malfunctioning components such as diodes or magnetrons.

Metal objects should never be placed inside a microwave as they can cause arcing and sparks which may lead to fire hazards and permanent damage to the appliance. If sparking occurs, immediately turn off and unplug the unit before removing any metal objects present inside.

Inspecting the waveguide cover is also crucial when addressing sparking issues in microwaves. Any signs of damage such as burns or charring on this cover should prompt you to refrain from using the appliance until repairs are made by qualified professionals.

Safety Precautions

When dealing with any issues related to microwaves—whether heating problems, intermittent operation, or sparking—it’s vital always remember certain critical safety precautions:

  • Always unplug the microwave before attempting any repairs or inspections.

  • Avoid touching internal components without proper knowledge and safety precautions.

  • In case of uncertainty about how to proceed with troubleshooting or repairs, seek assistance from qualified technicians who have expertise in handling electrical appliances like microwaves.

Resolving Door Issues

Proper Closure

Before using your microwave, always ensure that the door is fully closed and latched. A partially closed door can cause the microwave to malfunction and not heat up properly. This simple step is often overlooked but can make a significant difference in the performance of your appliance.

Check for any obstructions or debris around the door area that might be preventing it from closing properly. Even small objects or food particles can interfere with the door’s closure, leading to heating issues. Keeping the door and its surrounding areas clean and free from any blockages will help maintain proper functionality.

It’s essential to understand that even a slight gap due to improper closure can disrupt the microwave’s operation. So, take a moment before each use to ensure that you close the door securely.

Faulty Door Switch

The door switch serves as a crucial safety feature in microwaves, preventing them from operating when the door is open. If this component malfunctions, it could lead to unpredictable behavior such as the microwave not starting at all or stopping unexpectedly during operation.

If you notice any irregularities in your microwave’s behavior related to its starting and stopping patterns, it may indicate an issue with the door switch. Seeking professional assistance for diagnosing and potentially replacing this part is advisable if you suspect it may be faulty.

Remember that tampering with internal components of your microwave without adequate knowledge or expertise can be dangerous. Therefore, seeking help from qualified professionals ensures both safety and optimal functioning of your appliance.

Diagnosing Control Panel Problems

Functionality Verification

To ensure that the microwave is working properly after troubleshooting and repairs, it’s essential to test its functionality. One way to do this is by heating a small cup of water in the microwave. This simple test allows you to check if the microwave heats evenly and does so within a reasonable time frame. If the water doesn’t heat as expected, there may still be an issue with the appliance.

It’s crucial to verify that all buttons and settings on the control panel are working correctly. Press each button to confirm that they register your input accurately. Check different power levels, timer settings, and other functions available on your microwave to guarantee their proper operation.

  • Heat a small cup of water

  • Verify even heating and reasonable time

  • Test all buttons and settings

Error Code Interpretation

When facing issues with your microwave not heating up properly, error codes can provide valuable insights into the problem at hand. These codes offer specific information about what might be wrong with your appliance. To interpret these error codes accurately, refer to either the user manual provided with your microwave or visit the manufacturer’s website for detailed explanations.

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Once you have obtained information about an error code displayed on your microwave’s control panel, take appropriate action based on this knowledge. Whether it requires resetting certain components or seeking professional assistance from a technician will depend on the nature of the error code received.

Magnetron Specifics

Identifying Faulty Magnetron

If your microwave is not heating up properly, it could be due to a faulty magnetron. Signs of a problematic magnetron include the appliance not heating at all, heating food unevenly, or making strange noises during operation. If you notice any of these signs, it’s crucial to consult a professional technician for an accurate diagnosis and potential replacement. Attempting to replace the magnetron yourself is highly discouraged due to the high voltage risks involved.

A faulty magnetron can cause frustration when trying to heat up meals or beverages in your microwave. If you find that your food remains cold after running multiple cycles or if there are noticeable hot and cold spots in your dish after microwaving, this could indicate issues with the magnetron. If you hear unusual buzzing or humming sounds coming from the microwave during operation, it might point towards a malfunctioning magnetron.

Consulting a professional technician will ensure that the issue is accurately diagnosed and resolved without putting yourself at risk of electrical hazards associated with handling high-voltage components like the magnetron.

Replacement Process

Replacing the magnetron involves disassembling the microwave and accessing its internal components. It’s essential to follow manufacturer instructions meticulously or seek professional assistance for safe replacement. Manufacturers provide specific guidelines for replacing parts within their microwaves; therefore, adhering to these instructions ensures safety and proper functioning post-replacement.

When considering replacing the magnetron, taking necessary precautions against electrical hazards is paramount. This includes unplugging the appliance before starting any disassembly work and potentially using insulated tools when handling internal components. Seeking professional help guarantees that proper safety measures are taken into account throughout this process.

High Voltage Diode and Door Switch Details

Diode Failure Indicators

A faulty microwave diode can manifest in various ways. If your microwave won’t heat up, or if you notice sparking or a burning smell inside the appliance, it could indicate a problem with the diode. These signs point to potential issues that require attention from a professional technician. It’s crucial to seek accurate diagnosis and replacement by an expert to ensure safety and proper functioning of the microwave. Due to the electrical risks involved, replacing a diode should be handled by a qualified individual.

If you’re experiencing any of these issues, it’s important not to attempt repairs on your own without proper expertise. Trusting a professional ensures that the problem is addressed effectively while minimizing any potential hazards associated with handling high voltage components.

  • Signs of faulty diode:

  • No heat

  • Sparking

  • Burning smell inside the microwave

Switch Replacement Steps

When dealing with faulty door switches, accessing the control panel area of your microwave becomes necessary for replacement. Following manufacturer instructions or seeking assistance from a professional will help ensure safe and effective switch replacement. Before attempting any repairs, always remember to disconnect power from the appliance.

Replacing door switches involves delicate procedures that need careful attention for successful execution. Therefore, relying on expert guidance or assistance can prevent accidents and further damage to your microwave.

  • Steps for switch replacement:

  1. Access control panel area

  2. Follow manufacturer instructions or seek professional help


Addressing Other Microwave Anomalies

Common Miscellaneous Issues

Microwave not heating could be due to a faulty power supply or circuitry. When the microwave doesn’t receive enough power, it won’t be able to generate the heat necessary for cooking. Overheating issues can also cause the microwave to shut off prematurely as a safety measure. If the control panel buttons are malfunctioning, it can affect the overall functionality of the microwave, including its ability to heat food properly.

Another common issue is when there are problems with the control panel buttons. These buttons play a crucial role in setting cooking times and temperatures. If they’re not functioning correctly, it can lead to an inability to operate certain features of the microwave, including heating functions.

Blown fuses within microwaves can also lead to heating malfunctions. A blown fuse disrupts the flow of electricity needed for generating heat inside the appliance. It’s essential to check for blown fuses in your microwave’s internal fuse box if you suspect this may be causing your heating problem.

Component Blown Fuses

When dealing with component blown fuses in microwaves, it’s important first and foremost that these components have stopped working because they’ve been overloaded by too much electrical current passing through them.

  • To rectify this issue, you should carefully check for any signs of damage on these components.

  • If you find that one or more fuses have indeed been damaged or broken due to overloading issues, make sure that they’re replaced promptly with ones possessing appropriate type and rating.

  • This will ensure that your microwave is receiving just enough electrical current without being overwhelmed by excessive amounts which would otherwise blow its fuses again.


You’ve now uncovered the ins and outs of microwave heating issues, from component failures to fixing a non-heating microwave. By delving into the specifics of magnetrons, high voltage diodes, and door switches, you’re equipped to tackle these problems head-on. Remember, safety always comes first when dealing with electrical appliances, so don’t hesitate to seek professional assistance if needed.

Now it’s time to put your newfound knowledge into action. Take a look at your non-heating microwave armed with these insights and get ready to troubleshoot like a pro. Don’t let a malfunctioning microwave dampen your culinary adventures – with the right know-how, you can bring it back to its full heating potential in no time!

Frequently Asked Questions

Why is my microwave not heating up?

Microwaves may stop heating due to a faulty magnetron, high voltage diode, or door switch. These components can wear out over time and require replacement by a professional technician.

How do I fix a non-heating microwave?

First, check the power supply and ensure the door is closing properly. If these are not the issues, it’s best to contact a qualified technician for repairs as dealing with high-voltage components can be dangerous.

What could cause intermittent operation in my microwave?

Intermittent operation might result from loose wiring connections or failing electronic components. It’s crucial to have an experienced technician inspect and diagnose the problem for safe and effective resolution.

How can I address control panel problems in my microwave oven?

Control panel issues may arise from circuitry malfunctions or keypad defects. To avoid causing further damage, seek professional assistance to accurately identify and resolve these complex electrical problems.

Yes, worn-out door seals or misaligned hinges can lead to heat leakage, affecting the overall performance of your microwave. It’s essential to have these components inspected regularly by a professional technician for optimal functionality.