Hi:
Above unit is 3 years old, and for some time has had a problem of the freezer being much colder than I desire, and resetting the thermostat &/or freezer vent controls do not cause any change. Even with thermostat knob set for warmest setting (almost off), the fridge temp is 40F, and the freezer is 0f.
If I turn thermostat to a colder setting, the freezer can go down to -5F.

I replaced the thermostat in the fridge, but it did not change anything. I checked both the old & new stats for continuity, and they did function.

Any idea as to what else might be causing such a problem?

Well, my fridge seems to be improved after replacing the thermostat, though the freezer remains colder than I desire.
Though I don't quite understand it, I spoke with the manufacturer help line, and they tell me that the freezer unit is designed to maintain a temperature of 0 degrees, and the thermostat somehow controls only the fridge temp. Like I say, I don't understand how the freezer doesn't have a thermostat control of it's own, yet still maintains a constant temp.
Atleast my freezer is no longer < 0 degrees------an improvement.