6 Reasons Why Kenmore Microwave Not Heating – Let’s Fix It

Don’t be disappointed if your home microwave oven has been experiencing problems. There are a number of reasons why a Kenmore Microwave Not Heating. In this article, I’ll address the most common issues and give you some tips on how to troubleshoot the microwave oven.

When your microwave runs but doesn’t heat, it can be extremely frustrating. Many people assume that the microwave is broken when they first run into the problem, but there are a few things you can check out first before calling in an appliance repairman.

Your Kenmore microwave might not be heating up because of a couple of reasons. The most common reasons why a microwave is not heating up are a defective high voltage diode, the door switch, the magnetron or some other minor component. A qualified technician can usually figure out which piece needs replacement and will do so safely, even if replacing the part requires opening the machine cavity.

Kenmore Microwave Not Heating – Troubleshoot and Diagnosis

IMPORTANT: Even when a microwave is unplugged, it contains deadly voltage. You should never turn on an unplugged microwave to attempt any of the following fixes. Doing so can result in serious injury. Only qualified professionals should tinker with Kenmore microwaves.

While microwaves are complicated appliances, there are some important things that you should know about before making a repair call:

• Ensure that Timer function is not ON
  Sometimes, it happens. You hit the timer when you were supposed to hit the cook button. The timer is not a cooking tool — it’s a countdown monitor, and it only works when there’s nothing in the microwave.
• Ensure that door is properly closed
  The microwave door may not be closed or shut completely. Make sure the door is shut completely even if it seems like it is already closed. If there is a gap between the microwave and the door, it may affect the function of the microwave to cook food correctly.

There are a few reasons why your microwave might not be heating up:

Faulty Diode

If your microwave does not heat food, a defective high voltage diode may be the cause. In this case, your microwave might have shorted out from overheating. It’s recommended that you replace the diode to avoid potential damage to the magnetron or risk of fire or electrical shock.

When the microwave diodes fails, you can likely see it visually blown. Inspect the microwave diode and if the diode is blown away, replace it. If the diode seems to measure correctly with a multimeter, put a 9-volt battery in series with it. A multimeter will likely say that the voltage is not connected, but the diode should only conduct electricity in one direction while the leads are switched.

Defective Door Switch

Your microwave most likely has three to four door switches. The Door Switch is a very simple device that monitors the opening and closing of the door, which ensures that the microwave operates safely. If the microwave doesn’t heat, check the door switches. The door switches are located in each door and are part of the timer assembly. Check continuity of each switch. If a switch does not have continuity, replace it.

Burnt Out Magnetron

The magnetron is the most important microwave component. It’s a special type of vacuum tube that creates microwaves, which then heat up food. It’s like a tiny microwave oven in its own right. The magnetron can fail in several different ways. In some cases, it can burn out. Without a working magnetron, the microwave won’t work at all and must be replaced to restore functionality.

Burnt Out High Voltage Capacitor

The high voltage capacitor is used to filter the voltage. It allows the capacitor to work with the diode to convert the microwave output into a direct current power supply that can be used for cooking food.

If your microwave isn’t heating, one of the first things you should check is the capacitor. If the capacitor is burned out, it can lead to a total failure of the high voltage circuit and the microwave won’t heat. The first step to troubleshooting this issue is testing the capacitor with a VOM (volt-ohm-meter) and checking that the capacitor is indeed bad.

Failed High Voltage Transformer

Some of you might be not familiar with the term microwave high voltage transformer. It’s used to transfer the power from one circuit to another. If it malfunctions, then there will be a burning smell and smoke.

Blown Thermal Fuse

The thermal fuse is a component that protects the microwave from overheating. When the microwave is overworked, it generates more heat than it can dissipate, which can destroy the microwave. The thermal fuse prevents this from happening by cutting off power to the microwave whenever it notices more than a certain amount of heat inside the box. To test for continuity, use a multimeter. If you find no connection through the fuse, replace it with a new thermal fuse.

Tripped Thermoprotector

If the thermoprotector is tripped, it means that your microwave has overheated due to faulty wiring. This can lead to a fire. You may need to check the wires connecting the heating element and fan motor to see if they are damaged. But do not disassemble the microwave on your own; contact a licensed electrician.