My refrigerator does not defrost. I check bi-metal Thermostat and it check good (at 0 deg F 8was almost 0 ohm which is closed). Also check heater element check good 20.5 ohms. Put refrigerator in self test mode, Step 7 read 1 due to bi-metal were closed and heater did turn on and also measure 118 Volts across heater. Does this mean I have issue on main control board relay issue or microprocessor.