I have a E-lux freezer ( same manufacter as Whirlpool ) which was stuck in "super"-mode ie the thermostat was bypassed. By a local dealer I learnt that it was quite common the electronic failed but sometimes you could fix it by letting the freeze be unplugged for a couple of hours, and that worked for me once.
I don't know if that can help you but at least it's free to try.
Sorry to say a similar problem appeared later and now I had to replace the electronic unit ( easy done but 100$ for the unit.. )
Magnus
August 2005