Are you wondering why your microwave is not heating or what you can do about this problem? Well, you have come to the right place. In this article, we are going to talk about why your microwave is not heating and what you can do to fix it.
Table of Contents
What Could Cause a Microwave to Not Heat?
If your microwave is not heating, it could be because of the diode, magnetron, capacitor, thermal or line fuse, or the control board. If any of these components are bad, the microwave will not heat. We are going to talk about each of these components and how to replace them.
Microwave is Not Heating [Repair Cost]
If you want to contact a technician to fix this problem, it could range anywhere from $50 – $500. However, if you carry out the repair yourself, it won’t cost as much. But, if you don’t have any experience in microwaves, do not carry out the repair yourself.
How to Fix a Microwave That is Not Heating
To fix a microwave that is not heating, you will need to know which component is faulty. So check the following components…
The Diode
To inspect and replace the diode in a microwave, do the following…
Step 1: First, turn the microwave off and unplug it.
Step 2: Using a screwdriver take out the screws at the top of the front grille that hold it in place.
Step 3: Take out the grille.
Step 4: Open the microwave door then take out the screw above the control panel.
Step 5: Lift the panel up then out.
Step 6: Take out the screws that secure the inner access panel.
Step 7: Remove the inner access panel.
Step 8: Before going any further, you will need to discharge the electrical charge in the capacitor to avoid the risk of any injury. Do this by placing a screwdriver across the two terminals of the capacitor. Make sure that the screwdriver has an insulated handle.
Step 9: Remove the screw that secures the diode.
Step 10: Use a pair of needle nose pliers to disconnect the diode from the capacitor. If the diode is bad, it will be obvious because there will burn marks on it or it might be a bit melted.
Step 11: If the diode is bad, get a new one and connect it to the capacitor.
Step 12: Secure the diode using the screw.
Step 13: Return the inner access panel and hold in place with the two screws.
Step 14: Push the control panel back in and return the screw above it.
Step 15: Reinsert the front grille and secure it with the screws.
If you microwave is not heating after you have followed these steps, keep reading.
Note: If your microwave is not heating after a power outage, it means that the fuse may have blown.
Watch the video below for a visual of how to replace a microwave diode.
The Thermal Fuse
To replace the thermal fuse in a microwave, do the following…
Step 1: Unplug the microwave.
Step 2: Open the door of the microwave and take out the screws at the top of the front grille. There could be two or three screws depending on your microwave model.
Step 3: Take out the front grille and set it aside.
Step 4: Using a screwdriver take out the screw beside the control panel and loosen the other one behind it.
Step 5: Lift the control panel up then out.
Step 6: Disconnect the wires from the thermal fuse.
Step 7: Remove the screw that secures the thermal fuse to the microwave.
Step 8: Get a new thermal fuse and secure it with the screw you removed.
Step 9: Reconnect the wires to the fuse.
Step 10: Insert the tabs on the sides of the control panel back into the slots and push down to lock.
Step 11: Tighten the screw behind the control panel and return the other one beside it.
Step 12: Return the front grille and the screws.
keep reading if your microwave is not heating.
The video below will show you how to replace a microwave thermal fuse.
The Line Fuse
If the line fuse in your microwave blows, your microwave could stop heating. To know how to replace the line fuse in a microwave, do the following…
Step 1: Unplug the microwave
Step 2: Take out the screws at the top of the microwave front vent. There will be either two ro three screws.
Step 3: Take out the screw above the control panel then lift the panel up and out.
Step 4: Disconnect the thermistor wire from the control board to be able to move the control panel aside.
Step 5: Place a small piece of cloth under the fuse to prevent it from falling into the blower when you pry it out.
Step 6: Gently pry the old fuse out.
Step 7: Use a multimeter to test for continuity. If there is no continuity, you need to replace the fuse.
Step 8: Get a new fuse and place it in the holder.
Step 9: Reconnect the thermistor wire to the control board.
Step 10: Push the control panel back in and secure with the screw.
Step 11: Return the front grille and the screws.
Step 12: Close the microwave door.
If your microwave is not heating still, read on to see if you need to replace the control board.
The video below will show you how to replace a microwave line fuse.
The Capacitor
If your microwave is not heating, it may be because of a faulty capacitor. Before you replace this component, note that it stores a dangerous amount of energy which could cause injury or death if you do not take the proper precautions. To replace the capacitor in a microwave, do the following…
Step 1: Turn the microwave off and unplug the microwave.
Step 2: If your microwave is install in a cabinet, you will need to uninstall it. Open the door of the cabinet.
Step 3: Take out the bolts which hold the microwave cabinet. Have someone support the microwave as you do this.
Step 4: Tilt the microwave forward and pass the power cord through the hole in the cabinet.
Step 5: Lift the microwave up from the mounting plate on the wall.
Step 6: Place the microwave on a sturdy surface lined with a towel.
Step 7: Take out the screws at the top of the microwave front vent.
Step 8: Open the microwave door and remove the front vent.
Step 9: Take out the glass tray and support from the microwave.
Step 10: Close the door of the microwave.
Step 11: Lay the microwave on its back and take out all the screws which hold the bottom of the panel in place.
Step 12: Disconnect the wire harness.
Step 13: Take out the bottom panel.
Step 14: Turn the microwave back up.
Step 15: Take out all the screws at the sides, top, and back of the microwave which hold its cover in place.
Step 16: Lift the microwave cover up and remove it.
Step 17: Before you go any further, discharge the capacitor. You can do this by placing a screwdriver or a pair of pliers over the two terminals of the capacitor simultaneously.
Step 18: Note where each wire goes on the capacitor then disconnect them.
Step 19: Take out the screw which secures the capacitor to the microwave.
Step 20: Remove the capacitor and the mounting bracket.
Step 21: Test the capacitor using a multimeter, if there is no continuity when you do this, get a new capacitor. Click here to know how to test a capacitor using a multimeter.
Step 22: Transfer the mounting bracket from the old capacitor to the new one.
Step 23: Screw the capacitor back into place.
Step 24: Reconnect the wires to the appropriate terminals of the capacitor.
Step 25: Make sure that the microwave power cord is secured.
Step 26: Return the microwave cover and secure with all the screws.
Step 27: Rest the microwave on its back.
Step 28: Return the bottom panel of the microwave.
Step 29: Reconnect the wires then screw the bottom panel back into place.
Step 30: Turn the microwave back.
Step 31: Return the front vent and the screws which secure it.
Step 32: Lift the microwave up and sit it on the mounting bracket.
Step 33: Pass the power cord through the hole in the cabinet.
Step 34: Secure the microwave to the cabinet using the bolts.
Step 35: Return the glass tray and support to the microwave.
Step 36: Plug the microwave back in.
If your microwave is not heating still, keep reading.
The video below will show you how to replace a microwave capacitor step by step.
The Magnetron
Your microwave may not be heating because of a faulty magnetron. The magnetron is very expensive to replace, so if your microwave is old, you should consider replacing it if the magnetron is the faulty component. To replace the magnetron in a microwave, do the following…
Step 1: Unplug the microwave from the outlet.
Step 2: If your microwave is installed to a cabinet, you will need to uninstall it. Open the cabinet door and take out the bolts which secure the microwave to it. Make sure someone else is supporting the microwave as you do this.
Step 3: Gently tilt the microwave forward a bit and pass the power cord though the hole in the cabinet.
Step 4: Lift the microwave up and place on a flat and sturdy surface lined with a towel or cloth.
Step 5: Using a screwdriver, take out the screws which hold the front grille of the microwave in place.
Step 6: Open the microwave door and remove the front grille.
Step 7: Take out the glass tray and support from the microwave.
Step 8: Close the microwave door and lay the microwave on its back.
Step 9: Take out all the screws which hold the bottom panel of the microwave in place.
Step 10: Disconnect the wire harness to fully remove the bottom panel.
Step 11: Turn the microwave back to its upright position.
Step 12: Take out all the screws at the top, back, and sides of the microwave which hold the cover in place.
Step 13: Remove the microwave cover.
Step 14: Discharge the capacitor. Do this by placing a pair of pliers over the terminals of the capacitor simultaneously.
Step 15: Disconnect the wire or wires from the magnetron. If the magnetron has more than one wire, note where each one goes.
Step 16: Using a screwdriver, take out the screws securing the magnetron.
Step 17: Take out the magnetron and disconnect the wires connected to the thermal protector.
Step 18: Take out the screws which secure the thermal protector to the magnetron.
Step 19: Test the magnetron using a multimeter. If you do not know how to do this, click here
Step 20: If the magnetron is faulty, get a new one.
Step 21: Screw the thermal protector to the new magnetron.
Step 22: Take the magnetron back to the microwave and reconnect the wires to the thermal protector.
Step 23: Position the magnetron and hold it in place with the screws.
Step 24: Reconnect the wire or wires to the right terminals of the magnetron.
Step 25: Ensure that the power cord is secured.
Step 26: Return the microwave cover and hold it in place with the screws.
Step 27: Lay the microwave on its back again and return the bottom panel.
Step 28: Reconnect the wire harness and screw the bottom panel in place.
Step 29: Turn the microwave.
Step 30: Return the front grille and secure using the screws.
Step 31: Lift the microwave up and sit it on the mounting plate.
Step 32: Pass the power cord through the hole in the cabinet.
Step 33: Secure the microwave to the cabinet with the bolts.
Step 34: Return the glass tray and support to the microwave.
Step 35: Plug the microwave back in.
Watch the video below if you would like a visual of how to replace a microwave magnetron step by step.
The Control Board
To replace the control board in a microwave, do the following…
Step 1: Turn off the microwave and unplug.
Step 2: Remove the screws at the top of the front vent that holds it in place.
Step 3: Take out the vent.
Step 4: Take out the screw above the control panel.
Step 5: Lift the panel up then out slowly.
Step 6: Note where each wire goes on the control board, then disconnect each one. To make sure you connect the wires to the right places later on, you can take a picture.
Step 7: Remove the screw that secures the grounding wire in order to remove the control board.
Step 8: Install a new control board and screw the grounding wire to it.
Step 9: Connect the wires to the right places on the control board.
Step 10: Put the panel back and return the screw above it.
Step 11: Return the front vent and the screws.
Note: In a few cases, a faulty control board could cause your microwave to stop heating. Before replacing this part, call a technician to determine if this is really the cause of the problem.
The video below will show you how to replace a microwave control board.
Check out these articles…
Microwave Won’t Turn On [How to Fix]
Microwave Door [Problems & Solutions]
Microwave is Not Working [Various Problems Solved]
Microwave Oven is Making Noise [Various Issues Solved]
How to Install an Amana Microwave [Quick Guide]
Microwave Not Heating and Smells
If your microwave is not heating food and has a burnt smell, do not attempt to repair this yourself as it could be very dangerous. A burning smell in your microwave means that some electrical components are failing. Either contact an experienced technician to inspect it, or get a new microwave.
