The part(s) or condition(s) listed below for the symptom Microwave light bulb not working are ordered from most likely to least likely to occur. Check or test each item, starting with the items at the top of the page.
The light bulb itself might be burned out. Replace the light bulb before replacing any of the parts associated with the light bulb
Before replacing the control, check the light bulbs, sockets, and wiring. If these parts seem to be working properly, test the control board with a multimeter to determine if it sending the correct voltage to the light bulb socket. If the control board is not sending enough voltage to the light bulb socket, replace the control board.
Before replacing the light socket, replace the light bulb. If you replace the light bulb, and the light still doesn’t work, use a multimeter to test the light socket for continuity. If the light socket does not have continuity, replace it.