Disconnect the power to the microwave by unplugging it from the wall or turning off the circuit breaker.
Locate the light cover on the bottom of the microwave. If there is one light, the cover will be in the center of the underside of the microwave; if there are two lights, they will be on each side of the bottom surface.
Remove the screw on the side of the light cover, then remove the light cover.
Unscrew the burned-out light bulb, and discard it.
Screw the new light bulb into the light socket, then replace the cover and secure it with the screw that you removed. Restore power to the microwave to complete the replacement.
Disconnect power to the microwave by unplugging it from the wall or turning off the circuit breaker.
Remove the two screws on the grill at the top of the microwave. The screws will be either on the front or the top of the grill.
Remove the carbon filter behind the grill by pulling it toward you.
Remove the two screws securing the inner grill, which will be exposed now that the outer grill is removed.
Remove the screw from the rear of the left side of the air duct, using the offset Phillips screwdriver. Remove the air duct.
Lift the thin metal housing below where the air duct rests, and gently pull the light assembly out. Do not disconnect the cables that are connected to the light assembly.
Remove the burned-out light bulb, and insert the new light bulb. Reinstall all the components you removed to get to the light.