To check if the thermister is causing any problems, just let it dangle inside the refrigerator for 24hrs. The refrigerator should work as hard as it can and after 24hrs, it will be as cold as it's going to get. With the thermister in place, when it gets cold, it signals the control board to turn off the cooling process.
Don Ford
2004 Safari Trek 31SBD (F53/V10 20,500GVW)
'09 HHR 2LT or '97 Aerostar MiniVan (Remco driveshaft disconnect) for Towed vehicles
BlueOx Aventa II Towbar - ReadyBrake Inertia Brake System