The Defrost Thermostat Kit is an OEM part for Whirlpool refrigerators. It regulates the temperature in the freezer during the defrost cycle, ensuring that the defrost heater activates to melt any frost buildup and then turns off to maintain the proper freezer temperature. This thermostat opens at 42°F and closes at 30°F. This mechanism allows for short, controlled heating periods to melt frost without affecting the contents of the appliance. You should replace this defrost thermostat kit if it becomes defective. Common causes of a bad defrost thermostat include electrical failures, prolonged exposure to extreme temperatures, or wear and tear over time. Symptoms of a bad defrost thermostat include: Frost buildup in the freezer The refrigerator running continuously without cycling off The freezer not maintaining the correct temperature Water leaks from the freezer during the defrost cycle This OEM part is also compatible with Maytag, KitchenAid, Jenn-Air, Amana, Magic Chef, Admiral, Norge, Roper, and Kenmore models.This part fixes the following symptomsFreezer not defrostingFreezer too coldFridge too warmFreezer section too warm12001937 (AP4009073) replaces 1023500, 67001202, 67002571, 8170904, AH2003451, EA2003451, PS2003451.