Did you find out what was the problem? I'm having a similar problem. Refrigerator temp. 32; freezer -5.

I replaced the main board, all 3 thermistors and the defrost heater. Didn't help with these symptoms: After running smoothly for a couple of days, the freezer motor kicks into high for many hours, freezing food in the refrigerator section. Prior symptoms included a frosted freezer section and frozen water line inside the freezer door. The freezer section is not showing any new signs of frosting over, but I just defrosted it when replacing the parts. The lower coils behind the back wall did have frost on them, too. I have already had one repairman give up on repairing this frig., even with the help of GE technical support. It is 4-5 years old.

Any suggestions?