I have a GE side by side, Model GSL25JFTABS that is having cooling issues with the freezer. Will not go below 30 degrees. I have replaced the two thermistors in the freezer section, temp sensor & defrost, first, but saw no change. I just replaced the main control board hoping it would solve my problems, but Im still seeing no change. Also, I dont have any ice buildup on the evaporator coils, but only the bottom of the coils gets frosty. Any ideas?