Hi,Welcome to Just Answer, My name isXXXXX will be helping you with your appliance issue today.
You need to replace the damper assembly in this, GE has had to come out with a new updated damper assembly because of failure and freezing in the refrigerator section,this is what they write about it will you buy the parts you will see what it says and this is what it says.
Refrigerator air inlet cover/damper kit with fan motor. Damper and fan assembly have been updated to prevent freezing in the refrigerator. These are failing in every refrigerator need to be replaced, sometimes you can get GE to send you one at no cost if you call them, sometimes they will do it depending on the age of the refrigerator, but it's worth a shot, if they won't send it to you you can order it at this blue link. http://www.repairclinic.com/PartDetail/Damper-and-Fan-Assembly/1055112?modelNumber=GSS25PGMFWW these can be a pain to install also so keep that in mind, it is part number 459 on this diagram, thanks and well wishes, Bryan