Had a repair person come out and the problem said was the electric control which is electronic .installed new one ..my question on the evaporator coils they have frost on them are they supposed to be frost free .the fan comes on I take it comes on when the compressor comes on . The freezer temp is zero when the fans not on Then it is 10 .refrigerator at 40 .when we instAlled the new control electric the fAn didn't come o. So I took the back in the freezer with refrigerator off and manually defrosted as lots of ice on the evaporator coils .once done the fAn is working .but question about the frost .just wonder if it is a defroster heater or ? if it not supposed have any frost .