I have a Samsung RF217ACRS/XAC french door bottom freezer with an odd issue. The freezer is getting very cold, in fact it will freeze things left in the crisper on the fridge side, yet the display reads 30°C. I think the freezing issue is related to the unit believing it's not cold enough in the freezer and working overtime.
I have replaced the defrost thermistor on the advice of a parts source, only to realize after that had no effect that there is an ambient sensor on the "ceiling" in the freezer. That seems to test fine, but I swapped the other thermistor in there just to see what would happen. It instantly read 28°C, so i was hopeful it would drop as the freezer ran, but after an hour it's gone back to reading 30°C just like the other one. Frustrated and not sure what else to do... I pulled the board and inspected for any poor connections or broken wires, didn't see any.