I have a GE side by side refrigerator, model GSL22JFTABS that is having defrost and refrezzing issues. The freezer with defrost and refreeze frequently leaving ice accumulation on my food. I have replaced both the thermistor (WR55X10025) and high limit thermostat (WR50X10068) and still have the issue.Is there anything else I can try? Replace main board? Defrost heater?Any help would be greatly appreciATED.