Abstract: Plastic mold heater moisture detection and dry out apparatus for detecting the presence of moisture in the plastic molding heaters and for drying out the heaters. The plastic mold heater moisture detection and dry out apparatus includes a heater leakage current sensor, an analog to digital converter, a microprocessor, and a triac that are operatively connected to a heater temperature sensor and the heaters. The plastic mold heater moisture detection and dry out apparatus monitors the heater leakage current that is due to moisture or the like present in the heaters and depending upon the value of this leakage current either permits normal heater operation, dries out the heaters or shuts off power if an unsafe ground fault situation exists. In drying out the heaters a series of increasing voltages are applied to the heaters during successive loops or passes to avoid heater electrical arcing that could damage and degrade the heaters.