Replace light bulbs in a microwave by locating the cover plate shielding the light. Depending on the make and model, the cover plate may be located inside the cooking compartment or accessible from the back of the appliance. Refer to the owner's manual if necessary.
Begin by unplugging the unit. As a safety precaution, wait several moments to unscrew the cover plate. Once you have removed the plate, take out the dead bulb by unscrewing it one quarter turn to the left and pulling the base straight out. Examine the bulb to ensure you have the correct replacement. Like automotive bulbs, those found in microwaves have two prongs and are readily available at a local hardware store. Push in the new bulb, and rotate it one quarter turn to the right. Screw the cover plate back on. Plug in your microwave, and open the door. The lighting should now be functional.
When replacing the microwave bulbs, avoid all contact with the microwave's electronic circuit boards, generators, transformers and capacitors, which store energy. Even after the appliance is unplugged, the microwave may still carry high levels of voltage; touching a conductor of this voltage may result in personal injury or damage to the appliance.