How To Test And Replace The Door Switches On A Microwave

Posted on: 25 June 2015

Every microwave has switches that are activated when you close the door to your microwave. If the switches go bad, the electric circuit is disrupted and the microwave won't work. Here is how to check the door switches and replace them if necessary.

You Will Need:

  • Phillips Head Screwdriver
  • Ohms Meter

Safety First: You should unplug the microwave to avoid getting an electrical shock.

Remove Switches

Open the door on the microwave so you can remove the grill panel. The screws are located on the topside of the microwave. Remove the screws and slide the grill to the left to release it from its hinges.

You also need to remove the screws holding the control panel cover in place. One screw is located at the top left of the control panel and the other one is on top of the microwave behind the panel. Lift the control panel up to release it.

You will next need to remove the screws to the harness connecting the switch assembly to the internal frame of the microwave. Remove the screws and pull out the assembly.

The switches slide into the assembly. To remove a switch, you need to press down on the release tab on the back side of the assembly for each switch so you can pull them out of the assembly on the front side. Remove the wire connectors to completely detach the switch from the assembly.

Test Switches

You will want to test to make sure that the electrical connections in the switch are in working order.

Take your ohms meter and put the negative probe (colored black) on the common terminal (COM) – this terminal is located on the bottom of the switch next to the letters COM. Next, put the positive probe (colored red) on the terminal that has the letters NO (which means this terminal is normally open) on the side of the switch. Press down on the lever at the top of the switch. If you get a meter reading of zero, you have continuity. If nothing happens, you don't have continuity and the switch needs to be replaced.

You also need to test the switch when it is in its normally closed (NC) position. Place the negative probe on the COM terminal and the positive probe on the NC terminal. You should get a reading of zero to show there is continuity. When you press down on the switch lever, the ohms meter should stop responding. If the ohms meter reacts after you press down on the lever, the switch needs to be replaced.

Replace Switch

Make sure you have switches specifically manufactured for the type of microwave you have. Put the wire connector back onto the switch and slide it back into the assembly. Reattach the assembly, control panel, and grill panel to the microwave in the reverse order you took them apart. Close the door on the microwave and plug it back in. Turn it on to make sure the microwave is operating as it should. You are done. For more information on appliance repair, contact a professional like Shore TV and Appliance.