The Switch is an OEM part for Whirlpool microwaves. It controls the turning on and off of power to the microwave during cooking cycles as well as detects positions within cycles to signal appropriate actuations of the microwave's magnetron, fans, and lights. The switch is a crucial electrical component that facilitates the fully automatic operation of preset cooking programs.   Causes of a bad switch can include wear and tear over time or unexpected surges that cause electrical component failure. Symptoms of a bad switch include: Cooking programs failing to advance properly or stopping mid-cycle unexpectedly The microwave failing to turn on or experiencing power issues   Random noises, humming, or lights occurring when the microwave is supposed to be idle Buttons or controls acting intermittently unresponsive This OEM Whirlpool part can also be used on Maytag, KitchenAid, Jenn-Air, Amana, Magic Chef, Admiral, Norge, Roper, and Kenmore/Sears brand appliances.W10211972 (AP4357880) replaces 4375346, W10330566, WPW10330566, 1472224, 4393442, 4393498, 4393570, 4393697, 4393881, 461967848881, 8206345, AH2338920, EA2338920, PS2338920, W10131248, W10217468.