Abstract: Apparatus and method for detecting a failure in an automatic defrost system for a refrigerator. A current sensor means monitors the current supplied to the defrost heater and generates an "on" signal when current is sensed in the defrost heater circuit. A microprocessor determines the "off" time, that is the time between successive "on" signals, and compares this time to a predetermined reference time longer than the normal "off" time. A user discernible signal is generated upon detection of an "off" time greater than the reference time, signifying to the user that the defrost system is not operating properly, and corrective action may be necessary.