This video demonstrates how to test a three terminal switch on a microwave. The door switch is a commonly replaced part for a microwave that is not working. Other commonly replaced parts for a microwave that is not working:
Line fuse Main control board Thermal fuse Thermoprotector
All of the information provided in this part testing video is applicable to the following brands: Amana, Frigidaire, GE, Kenmore, LG, Maytag, Panasonic, Samsung, Sharp, Whirlpool
