Phil,
The GE OEM part number for the air damper is
WR49X10091. The most common problem that we see the cause the fresh food section to freeze is the air damper door breaking and not closing all of the way. The new air damper assembly has been improved and re-designed from the manufacturer. There is no way to test this part, but you can pull it off and do a visual inspection of the damper door, you can usually see where it is broken off. The two other parts that work with the air damper to control the temperature are the main control board (
WR55X10942), and there are two temperature sensors (
WR55X10025).
Here is how to replace the air damper (some steps vary by model):
Unplug refrigerator
Remove the top two shelves
Remove the top light cover, this will give you access to remove the top two screws on the damper
Some models have two screws behind the duct on the back of the refrigerator
You should be able to pull the damper out and disconnect the wiring harness going to it.
Reinstall in the reverse order
These are the parts for your model:
Air Damper & Fan Assembly - Part # PD00001003 (mfg # WR49X10091)
Main Control Board - Part # PD00000994 (mfg # WR55X10942)
Temperature Sensor (Thermistor) - Part # PD00000992 (mfg # WR55X10025)