frig not cooling

Refrigerator & Freezer Repair
,
1

i have a 3 yr old ge externa series side by side frig that isnt cooling properly. first signs of trouble was frig seemed to always run. then ice would not dispence . i noticed auger motor would not turn only hum, removed motor and found that it was frozen solid, let defrost and tested on bench worked fine, then vacuumed evaporator coil , put back together and it seemed to be working ok. i kept thermometers in freezer and frig and noticed temps had started rising . emptied contents unpluged it and working again. im thinking faulty thermister or mother board . any help would be appreciated