i am servicing a GE PGSS5PJYASS a year ago had replaced inverter for no cool. call states freezer fine, ref not cold. checked damper was open, ohmed thermister checked good. col air blowing from freezer...changed thermister...2 days go by was fine. went back and found damper closed. manually opened and disconnected power to damper...3 days cold now to 56 degrees freezer at 5 degrees...any ideas?