Whirlpool Microwave is Not Heating [How To Fix]

If your Whirlpool microwave is not heating, you have come to the right place. In this article, we are going to be talking about the main causes of this problem and how to fix it.

How to Fix a Whirlpool Microwave That Won’t Heat

There are a couple of reasons why your Whirlpool microwave is not heating. So in order to fix the problem, you will need to determine what component in the microwave is faulty.

The Line Fuse

The reason your Whirlpool microwave is not heating may be because of a blown fuse. So you will need to check and maybe change it if it is faulty. To do this, follow these steps…

Step 1: Turn off the microwave and unplug it.

Step 2: Using a screwdriver, take out the two screws that hold the top grille in place.

Step 3: Pull the grille out.

Step 4: Open the microwave door and take out the screw above the control panel that holds it in place.

Step 5: Lift the control panel up then out to remove.

Step 6: Take out the screws that secures the inner access panel.

Step 7: Remove the access panel.

Step 8: Before going any further, you should discharge the capacitor to avoid any fatal injuries. To do this, place a screwdriver with and insulated handle between the terminals of the capacitor.

Step 9: Use pliers to remove the old fuse.

Step 10: Using a multimeter, test the fuse for continuity. If the fuse has no continuity, you will need to replace it. However, if it does have continuity, return it.

Step 11: Place a new fuse in the bracket of the old fuse.

Step 12: Place the inner access panel back and secure with the two screws.

Step 13: Push the control panel back inside and secure with the screw.

Step 14: Snap the front grille back into place.

Step 15: Return the two screws.

Step 16: Turn the microwave on and place a cup of water in it.

Step 17: Set the microwave on the highest setting for one minute.

Step 18: After one minute, take out the cup. If the water is hot, you have fixed the problem. If your Whirlpool microwave is not heating still, the problem may be from one of the other components in the microwave.

The Diode

To replace the diode in a Whirlpool microwave, do the following…

Step 1: Turn off the microwave and unplug.

Step 2: Take out the glass turntable and support from the microwave.

Step 3: Have a second person support the bottom of the microwave as you take out the long bolts that hold the microwave to the cabinet.

Step 4: Remove the bolts.

Step 5: Tilt the microwave down and pull the plug from the hole in the cabinet.

Step 6: Lift the microwave up then set it on a flat sturdy surface.

Step 7: Lay the microwave on its back.

Step 8: Using a screwdriver, take out all the screws that hold the bottom panel of the microwave in place.

Step 9: Disconnect the wires to the turntable motor.

Step 10: Unhook the wires then disconnect the wire connector so that you can remove the bottom panel.

Step 11: Turn the microwave back and prop the front up using a plank or thick book.

Step 12: Open the microwave door and take out the screws hat secure the front grille.

Step 13: Pull the grille out.

Step 14: Take out all the screws securing the back of the microwave.

Step 15: Remove the two screws to take out the air damper cover.

Step 16: Take out the remaining screws at the top and the right side of the microwave.

Step 17: Remove the microwave cover.

Step 18: Discharge the capacitor by placing a screwdriver with an insulated handle across each terminal.

Step 19: Take out the screw that secures the diode to the frame.

Step 20: Disconnect the diode from the capacitor to fully take it out.

Step 21: Install the new diode by plugging it to the capacitor terminal then screwing into place.

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Step 22: Position the microwave cover back and return all the screws on the right side of the microwave.

Step 23: Reposition the air damper back and screw back tightly with the all the screws.

Step 24: Return the other remaining screws on top.

Step 25: Tighten the other screws at the back of the microwave to keep it in place.

Step 26: Push the front grille back into place and secure using the screws.

Step 27: Lay the microwave on its back again.

Step 28: Return the bottom panel and reconnect the wire connector.

Step 29: Hook the wires back in the retainer and connect the wires back to the turntable motor terminals.

Step 30: Close the terminal cover.

Step 31: Screw the bottom panel back into place.

Step 32: Hook the back of the microwave on the tabs on the wall.

Step 33: Take the power cord through the hole in the cabinet.

Step 34: Secure the microwave with the mounting bolts.

Step 35: Return the glass tray and support to the microwave.

Step 36: Do the water test. If your Whirlpool microwave is not heating still, keep reading.

Note: If your Whirlpool microwave is not heating, it may be because of the diode. The diode sends power to the magnetron in order for the microwave to heat. So, if the diode is faulty, the magnetron won’t receive enough power to operate.

The Door Switch

To replace the door switch in a Whirlpool microwave, do the following…

Step 1: Turn the microwave off then unplug.

Step 2: Open the microwave door and take out the three screws that hold the front grille in place.

Step 3: Pull the grille out.

Step 4: Take out the screw right above the control panel that holds it in place.

Step 5: Lift the control panel up then take it out.

Step 6: Disconnect the thermistor wire connector from the control board to move the panel out of the way.

Step 7: Take out the screws that secure the door switch holder.

Step 8: Using needle nose pliers, detach the interlock spring from the door switch.

Step 9: Take out the switch from the holder and disconnect the wires. Make sure to note where each one goes on the door switch.

Step 10: To test if the door switch is faulty or not, press the small button on it. If there is a strong click, the switch is still good. If not, you will need to replace it.

Step 11: Get a new switch and connect the wires to the right places.

Step 12: Place the switch back in the holder and snap into place.

Step 13: Reposition the interlock spring on it.

Step 14: Align the door switch holder on the frame and secure it with the screw.

Step 15: Connect the thermistor wire back to the control board and push the control panel back into place.

Step 16: Return the screw above the control panel.

Step 17: Push the front grille back in and secure it with the three screws.

Step 18: Do the water test.

If your Whirlpool microwave is not heating after this, keep reading.

The Capacitor

If your Whirlpool microwave is not heating, the capacitor may be faulty. Before replacing the capacitor, please note that it stores a dangerous amount of energy which could cause injury or death if you don’t take the right precautions. To replace the capacitor in a microwave, do the following…

Step 1: Turn the microwave off and unplug it from the outlet.

Step 2: Open the door of the microwave and take out the glass tray and support.

Step 3: 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 4: Tilt the microwave forward a bit and pass the power cord through the hole in the cabinet.

Step 5: Lift the microwave off the mounting plate on the wall and place on a flat and sturdy surface lined with a cloth or towel.

Step 6: Take out the screws at the top of the front grille which secure it.

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Step 7: Open the microwave door and remove the front grille.

Step 8: Close the door and rest the microwave on its back.

Step 9: Take out all the screws which hold the bottom panel of the microwave in place.

Step 10: Open the cover of the turntable motor terminals if there is one.

Step 11: Disconnect the turntable motor wires and make sure to note where each one goes.

Step 12: Unhook the other wires from the frame then disconnect them to remove the bottom panel.

Step 13: Turn the microwave back and prop the front with a plank or something thick.

Step 14: Take out the screws which hold the blower cover in place.

Step 15: Remove the blower cover.

Step 16: Take out the screws at the top, sides and back which hold the microwave cover in place.

Step 17: Remove the microwave cover.

Step 18: Discharge the capacitor. You can do so by placing a screwdriver with an insulated handle over the terminals simultaneously.

Step 19: Disconnect the wires connected to the capacitor. Also disconnect the diode.

Step 20: Take out the screws which secure the capacitor to the frame.

Step 21: Remove the capacitor and the bracket from the microwave.

Step 22: Remove the bracket from the capacitor.

Step 23: Using a multimeter, test the capacitor for continuity. If there is none, you will need to get a new one.

Step 24: Transfer the bracket to the new capacitor.

Step 25: Align the capacitor and bracket to the frame.

Step 26: Hold them in place using the screws.

Step 27: Reconnect the wires and the diode to the capacitor.

Step 28: Reposition the microwave cover and secure at the back, top and sides using the screws.

Step 29: Return the air damper and secure with the screws.

Step 30: Rest the microwave on its back and return the bottom panel.

Step 31: Reconnect the wires and hook them back in the frame.

Step 32: Connect the turntable motor wires to the right terminals.

Step 33: Return the cover and close it.

Step 34: Turn the microwave back up.

Step 35: Return the front grille, ensuring that the two support clips are in place.

Step 36: Secure it using the screws.

Step 37: Lift the microwave up and hook it back on the mounting plate.

Step 38: Pass the power cord through the hole in the cabinet.

Step 39: Secure the microwave to the cabinet using the bolts.

Step 40: Return the glass tray and support.

Step 41: Plug the microwave back in.

If you would like a visual of how to replace the capacitor in a Whirlpool microwave, watch the video below.

If your Whirlpool microwave is not heating still, keep reading.

The Thermoprotector

If your Whirlpool microwave is not heating, you should test and replace the thermoprotector. To replace the thermoprotector in a Whirlpool microwave, do the following…

Step 1: Turn off and unplug the microwave. Remove the glass tray and support from the microwave.

Step 2: Take out the bolts which secure the microwave to the cabinet. Have someone support the microwave as you do this.

Step 3: Gently tilt the microwave forward and pass the power cord through the hole in the cabinet.

Step 4: Lift the microwave up and place on a flat and sturdy surface.

Step 5: Take out all the screws at the top of the front grille.

Step 6: Open the microwave door and take out the front grille.

Step 7: Turn the microwave to rest on its back and take out all the screws which hold the bottom panel in place.

Step 8: Disconnect the wires connected to the turntable motor making sure to note where each one goes.

Step 9: Disconnect the other wires and unhook them from the frame to remove the bottom panel.

Step 10: Turn the microwave back.

Step 11: Take out the screws which hold the blower cover in place.

Step 12: Remove the blower cover.

Step 13: Take out all the screws which hold the microwave cover in place.

Step 14: There will be some at the back, top, and sides of the microwave.

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Step 15: Remove the microwave cover.

Step 16: Discharge the capacitor. Do this by placing a screwdriver over the capacitor terminals simultaneously.

Step 17: Take out the screws which secure the thermoprotector to the magnetron.

Step 18: Disconnect the wires connected to the thermoprotector.

Step 19: Using a multimeter, test the thermoprotector for continuity. If there is none, you will need to replace it.

Step 20: Get a new thermoprotector and connect the wires to it.

Step 21: Screw it back to the magnetron.

Step 22: Return the microwave cover and secure it with the screws.

Step 23: Reposition the blower cover and hold it in place with the screws.

Step 24: Return the front grille to the microwave and the screws at the top.

Step 25: Rest the microwave on its back and return the bottom panel.

Step 26: Reconnect the turntable motor wires. Also reconnect the other wires and hook them back in the frame.

Step 27: Screw the bottom panel back into place.

Step 28: Lift the microwave up and hook on the mounting plate.

Step 29: Pass the power cord through the hole in the cabinet.

Step 30: Secure the microwave to the cabinet with the bolts.

Step 31: Return the glass tray and support to the microwave.

Step 32: Plug the microwave back in.

The Magnetron

To test and replace the magnetron in a Whirlpool microwave, do the following…

Step 1: Unplug the microwave from the outlet.

Step 2: Take out the glass tray and support from within the microwave.

Step 3: Close the door.

Step 4: Have someone support the microwave as you take out the bolts which secure it to the cabinet.

Step 5: Tilt the microwave forward and pull the power cord through the hole in the cabinet.

Step 6: Lift the microwave off the mounting plate on the wall and place on a sturdy surface lined with a towel.

Step 7: Take out the screws which hold the front grille of the microwave in place.

Step 8: Open the microwave door and remove the front grille.

Step 9: Close the door and lay the microwave on its back.

Step 10: Take out all the screws which secure the bottom panel.

Step 11: Disconnect the turntable motor wires and make sure to note where each one goes.

Step 12: Disconnect the wire harness and unhook from the frame to fully remove the bottom panel.

Step 13: Turn the microwave back up.

Step 14: Take out the screws which hold the blower cover in place.

Step 15: Remove the blower cover.

Step 16: Also take out the screws which hold the microwave cover in place. There will be screws at the back, top, and sides.

Step 17: Lift the microwave cover and take it out.

Step 18: Discharge the capacitor by placing a screwdriver over the terminals of the capacitor simultaneously.

Step 19: Unscrew the grounding wire.

Step 20: Take out the screws at the back of the microwave which hold the air baffle in place.

Step 21: Remove the air baffle.

Step 22: Note where each wire goes on the magnetron then disconnect them.

Step 23: Take out the screws that secure the thermoprotector.

Step 24: Now take out the four screws which hold the magnetron in place.

Step 25: Remove the magnetron and test it with a multimeter. If there is no continuity, replace the magnetron. To know how to test the magnetron with a multimeter, click here  

Step 26: Get a new magnetron. Ensure that the seal is in place.

Step 27: Position the magnetron and hold it down with the screws.

Step 28: Screw the thermoprotector back to it.

Step 29: Reconnect the wires to the right magnetron terminals.

Step 30: Return the air baffle and screw it into place.

Step 31: Screw the grounding wire back.

Step 32: Make sure the power cord is in place.

Step 33: Reposition the microwave cover and return the screws at the top, sides, and back of the microwave.

Step 34: Position the blower cover and secure with the screws.

Step 34: Rest the microwave on its back.

Step 35: Return the bottom panel and reconnect the turntable motor wires.

Step 36: Reconnect the wire harness and hook back.

Step 37: Screw the bottom panel in place.

Step 38: Turn the microwave back up.

Step 39: Return the front grille and the screws at the top.

Step 40: Lift the microwave and hook on the mounting plate.

Step 41: Pass the power cord through the hole in the cabinet.

Step 42: Return the bolts which secure the microwave to the cabinet.

Step 43: Return the glass tray and support.

Step 44: Plug the microwave back in.

The video below will show you how to replace a Whirlpool microwave magnetron step by step.

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