Coils in freezer icing up. Cools fine after I manually defrost it, lasts a few days before it ices up again. I hear a clicking sound, fan seems to turn on for a second and then off, repeats. I see a defrost thermostat clipped on to the coils and apparently there is also a thermostat assembly elsewhere and a heating coil. A defrost timer as well? Any hints on testing components? Coil should have continuity, should the defrost thermostat be open (no continuity) or closed (continuity) at room temperature? Model # doesn't show on your parts lookup.