How to Fix a Microwave Touchpad That's Not Working

If the buttons on your microwave touchpad do not work, it may be an issue with the membrane switch. This part is made up of soft touch electrical switches, which are two layers of Mylar plastic with conductive coatings on the sides that face each other. When you press a key on your microwave touchpad, the two surfaces come in contact and complete an electrical circuit which sends a signal to the control board. The conductive coating on your membrane switch will wear out over time through repeated use, and need to be replaced. Unplug your microwave and remove the cabinet in order to access the membrane switch, which is usually attached to the control board. The membrane switch will most likely be connected to the control board with a flat ribbon connector, check this connection before proceeding. You should check the electrical schematic of your microwave for the matrix layout of the membrane switch before performing this test. Use a multi-meter to test the touchpad. There should be a few ohms of resistance when you test each key on the touchpad.

If you cannot key in numbers on your microwave touchpad but the display is still lighting up, it may be an issue with the control board. The control board supplies the touchpad with low voltage signals. When you press a button on your microwave touchpad, the control board sends a signal to the other microwave components to begin heating. If the membrane switch is functioning as usual, and the connection to the control board looks fine, then the control board likely needs to be replaced. Disconnect power and remove the cabinet and control assembly to replace it.