Upper right in photo, there appears to be a two-terminal plug off to side of circuit board that appears to be plugged into nothing, wonder if it was plugged into that at one time. Don't just randomly plug it in there though! You can pull your temp probe cable in your fridge and have someone watch to see what wire is moving, that's how I identified my temp probe wire.
The thermister (probe) is a pair of wires in a white protective shroud that go into a plug onto circuit board.