Unit is not cooling properly. All fans are running, no excessive dust build up and no ice build up in freezer compartment, cool air coming out but frozen food defrosted in freezer and food in frig portion warmer than desired. Removed back panel in freezer and turned defrost timer to defrost and fans kicked off but heater coils did not get warm. Did notice ice build up on coil that comes out of back wall on unit(from compressor) overnight, no ice on fins or other portions. Removed thermostat relay and measured with voltmeter and it reads 58 ohms(at 200 K setting). What should the reading be? If bad would a thermostat relay keep the compressor from running. Only noise I hear when unit is running is the fans, compressor does not appear to be kicking in.