Whirlpool Microwave Not Heating Food But Runs – How To Fix

Whirlpool microwaves are a lifesaver. But what if your Whirlpool microwave is not heating food suddenly?

Well, you should know you’re not alone in this. The issue is common – sometimes in its lifetime, your Whirlpool microwave won’t heat. It’s a situation most of us have faced.

You put your food in, the timer is ticking, the light is on, but the food comes out cold. You think, why is my Whirlpool microwave not heating?

However, I recently encountered the same issue with my microwave and managed to fix it. Now, I’d like to share the steps on how to resolve it when your Whirlpool microwave won’t heat up.

Well, let’s know what’s causing it and what you can do to fix this Whirlpool microwave problem.

Why Is Your Whirlpool Microwave Not Heating?

Remember, understanding the problem is half the battle won. So, to understand this issue, it’s crucial to understand how a microwave works, especially the Whirlpool microwaves.

In simple terms, microwave ovens use microwave radiation to heat food. The microwaves then excite the water molecules in your food, creating heat. This process is quick and efficient, so we love our microwaves.

What happens when your microwave runs but does not heat? When you put your food in the microwave, and it’s running (rotating its plate) without heating it, it means something is stopping it from generating microwave radiation.

There could be many factors behind this. It could be due to a faulty door switch or magnetron. Or a defective diode or capacitor could be the culprit. The power setting being incorrect can also be a cause for it.

Simply, there’s a lot to consider. So, what can you do when your Whirlpool microwave doesn’t heat? We’ll explore solutions in the following sections.

What To Do If Whirlpool Microwave Not Heating Food But Runs?

Are you wondering why is your Whirlpool microwave not heating? Let’s delve deeper into these common causes of why your Whirlpool microwave might not be heating.

1. Faulty Door Switches

Every microwave has interlock switches. They ensure the appliance only operates when the door is secure.

Suppose any of these switches fail. In that case, the microwave will act as if it’s functioning – it runs, but it doesn’t heat.

With my Whirlpool microwave, I faced this issue last year. After troubleshooting, I discovered one of the door switches had failed.

Troubleshooting it:

To detect a faulty switch, open and close the microwave door. If you don’t hear a click each time, one switch might fail. If that’s the case, unplug the microwave and remove the cabinet.

Then, check the wires running to the switch for any corrosion or rust. If you find any, you will need to replace the switch.


The solution? You can replace the faulty switch yourself or call a professional.

  • Unplug your microwave, remove the cabinet, and locate the door switches.
  • If you find a faulty switch (usually indicated by burn marks), replace it with a new one.
  • Remember to exercise caution while dealing with electrical components.

2. Broken Magnetron:

The magnetron is the heart of your microwave. It generates the microwaves that heat your food. If it’s broken, your microwave will run but won’t heat food.

A friend of mine experienced this with her Whirlpool microwave. Despite running, her microwave was not heating food. After some inspection, it turned out to be a faulty magnetron.

Troubleshooting it:

You can detect a broken magnetron by listening. The magnetron might be the issue if you hear a loud buzzing noise.

You can also measure the voltage of the magnetron. If the voltage is too low or too high, it could be an indicator that the magnetron has gone bad.


Unfortunately, fixing a magnetron isn’t a DIY job. It’s high voltage and dangerous. My advice? Hire a professional.

3. A Damaged Diode Might Be Your Problem:

The diode transforms the transformer’s A/C power output into a D/C, doubling the voltage to almost above five thousand volts. This high voltage powers the magnetron that heats the food.

So, if your diode burns out, your microwave might not heat, although it runs. I learned this the hard way when my microwave stopped heating.


You can test the diode using a multimeter. A suitable diode will show low resistance in one direction and high resistance in the other.

If it shows low resistance in both directions, it’s defective. Replacing a diode is a task you can do. But be careful. It can store a lethal amount of electricity.


If a damaged diode is causing your microwave not to heat, replacing it can solve your problem.

  • Unplug your microwave,
  • Discharge the high-voltage capacitor to avoid a dangerous electrical shock
  • Locate the diode
  • Replace it with a new one.

See More: Fix your Whirlpool microwave fan if it does not work properly.

4. The High-Voltage Capacitor Malfunction:

It stores electricity and works with the diode to increase the magnetron’s voltage. A malfunctioning capacitor means an inadequately powered magnetron. It leads to the microwave running but not heating.

Troubleshooting it:

Testing a capacitor is tricky. It involves discharging it, which can be dangerous. Then, using a multimeter, check for continuity. No continuity indicates a problem.

Again, replacing a capacitor can be a DIY job. But only if you’re comfortable working with high-voltage components.


If your microwave is running but not heating due to a malfunctioning high-voltage capacitor, you must replace it.

To do that, remember to discharge the capacitor before starting the replacement process. It stores high-voltage electricity even when the microwave is unplugged.

5. The Transformer Could Be Defective:

It steps up your house line voltage to two higher voltages. One powers the magnetron, while the other powers the Whirlpool microwave light and fan.

A defective transformer means a less efficient microwave. Your Whirlpool microwave may run but not heat.

Troubleshooting it:

To check a defective transformer, disconnect the microwave and remove the transformer. Test for continuity with a multimeter. If it’s faulty, you’ll need to replace it.

This task is doable, but it involves handling heavy parts. You should enlist help.


For a defective transformer, the best solution is a replacement. It’s technical, and you should consider hiring a professional.

But if you feel up to the task, unplug the microwave, remove the cabinet, locate the transformer, and replace it with a new one.

6. Thermostat Issues:

The microwave thermostat monitors the temperature and communicates it to the control board. So, thermostat issues can prevent your microwave from heating.

If it overheats during use, your thermostat might be the issue.

Troubleshooting it:

You can check it with a multimeter. A lack of continuity suggests a problem. If it’s defective, it needs replacing. It’s a task that requires precision, but it’s possible to do it yourself.

Alternatively, you can take it to a professional appliance repair technician for help if you’re not sure.


The solution for this is, as always, replacing the faulty thermostat. Unplug your microwave, remove the outer shell, locate the thermostat, and replace it with a new one.

Make sure to get the right thermostat for your model. Also, take safety precautions when working with electricity.

7. Control Board Problems Can Cause Issues:

The control board is like the microwave’s brain. It controls the voltage and the microwave’s various components. If it malfunctions, it might lead to the microwave running but not heating food.

It can also cause the microwave to spark or make a humming noise. Other problems that can arise from a faulty control board include display issues, unresponsive buttons, and error codes.

Troubleshooting it:

A burnt or shorted-out control board is usually the issue. You can check the connections to the control board for any signs of damage. Please make sure they are secure and not loose.

But detecting this is tricky without technical knowledge. To be on the safe side, get a professional to examine it. If it’s a problem, they can replace it for you.


For control board problems, resetting it may solve your issue. Unplug your microwave, wait a few minutes, then plug it back in. If this doesn’t work, you might need to replace the control board.

Also Read: How To Reset Whirlpool Microwaves: Quick and Simple Guide

So, are you still wondering, “Why is my Whirlpool microwave not heating?” It could be any of the reasons we just discussed. Remember, accurate diagnosis is the ultimate solution.

How To Avoid the “Microwave Won’t Heat” Problem?

Want to know how to solve this issue before it happens? Check below.

Regular Maintenance Tips:

Regular maintenance often prevents such issues.

Let me share some insights.

  1. First, clean your microwave often. Grease and food particles can lead to issues. For instance, did you know that built-up grime can absorb microwaves and affect heating? So, clean it regularly. Using a mild detergent helps. It removes dirt without damaging your microwave. Just dampen a cloth with soapy water, wipe the interior, and then dry it.
  2. Second, don’t slam the microwave door. I know; we often do this out of habit. But did you know a hard slam can damage the door switch? And a faulty door switch can lead to a situation where your Whirlpool microwave won’t heat. So, close the door gently.
  3. Third, always use microwave-safe dishes. Non-microwave-safe dishes can damage the microwave’s interior. They can also affect the heating.

Preventive Tips:

Prevention is better than cure. It’s an adage that holds for microwaves. So, how can we prevent common issues like a Whirlpool microwave not heating food but running?

Let’s discuss it below.

  1. Check the power settings before you start. Different foods need different power levels. If the power setting is too high, your microwave will wear down quickly and won’t heat properly. So, ensure you use the correct power setting for the right food.
  2. Next, make sure your microwave is on a flat surface. Did you know that vibrations can lead to loose connections inside your microwave? Yes, and that could be why your Whirlpool microwave is not heating.
  3. Lastly, don’t overload your microwave. Overloading can strain the microwave’s components.

It can even damage the magnetron – the heart of the microwave. And a faulty magnetron can lead to your Whirlpool microwave not heating.

Frequently Asked Questions [FAQs]

Is there any common issue that causes all Whirlpool microwaves not to heat up?

No, there isn’t a common issue specific to Whirlpool microwaves regarding heating problems. However, problems with the magnetron are standard in all types of microwaves, including Whirlpool.

Do I need a professional to fix my Whirlpool microwave if it’s not heating?

In most cases, yes. Some minor issues, like a blown fuse, can be fixed at home. But problems with the magnetron, diode, or capacitor are best left to professionals due to the high voltage involved and the risk of electric shock.

Can I still use my Whirlpool microwave if it’s not heating food?

No, there isn’t. In fact, using a microwave that isn’t heating food is not advisable. If the microwave isn’t heating, it’s not performing its primary function and indicates a more serious underlying problem that needs addressing.

Can a power outage or surge cause a Whirlpool microwave to stop heating?

Yes, a power outage or surge can cause damage to the microwave’s electrical components, resulting in it not heating. The solution for this is to follow the tips we have mentioned above.

Is fixing a Whirlpool microwave that’s not heating expensive?

The cost of fixing a microwave that’s not heating can vary widely. It’s based on the exact problem and the cost of replacement parts.

For example, replacing a magnetron can be expensive, often making replacing the entire microwave more economical than repairing it.

What are some signs that my Whirlpool microwave is about to stop heating food?

Some signs that your Whirlpool microwave might be about to stop heating food include longer than usual cooking times, unusual noises during operation, the door not sealing properly, and the keypad or control panel not responding correctly.

Can improper installation cause a Whirlpool microwave not to heat?

Yes, improper installation can cause a microwave not to heat. For instance, if the microwave isn’t adequately ventilated, it can overheat, causing the thermal cut-outs to trip and the microwave to stop heating.

The door may only close appropriately if the microwave is leveled correctly. It can prevent the microwave from heating due to safety mechanisms designed to stop operation when the door is open.

How long should a Whirlpool microwave last before it stops heating?

Under typical use, a microwave oven lasts about seven years. With heavy use and poor maintenance, it might need to be replaced every 4 to 5 years.

Should I replace my Whirlpool microwave if it’s not heating, or is it worth repairing?

If your microwave is over a couple of years old and has lost power, the magnetron can be in the final stages of its life, and it may prove more cost-effective to replace the appliance than to repair it.

Final Words

So, we dove deep into the problem of why is a Whirlpool microwave not heating. We’ve explored the workings of a microwave, the symptoms of the issue, and the possible causes.

In summary, any Whirlpool microwave’s components can cause it not to heat (but to run). The ultimate solution is to replace the faulty parts.

But remember, regular care and correct usage can go a long way in preventing issues in the first place. Our tips here can help ensure that.

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