My kenmore side by side was freezing up. I replaced the defost thermostat. The compressor runs and the coil inside the freezer ices over but the defrost fan never comes on. I have been told that when the thermostat goes that the timer will go soon after. I tested the fan while it was out of the fridge and it worked fine. My next thought is that the timer is not working properly but when you turn the dial manually it seems to be working right???? Any sugestions???