Answer Edward, The first thing that you will want to check is the coils in the freezer to check to see if they are impacted with frost. If they are you will want to test the defrost thermostat and defrost heater for continuity. If there is continuity then the parts are good and you will need the defrost control board. If either of those do not have continuity then it is bad and will need to be replaced. Read More... Answered by AppliancePartsPros.com | Wednesday, December 23, 2015