I have just had to dismantle the thermostat on my fridge on my B32 and it was a straight forward affair. The unit is connected via 2 wires, one of which has a small resistor soldered to the end between the spade terminal and the wire so be careful when removing it. My own fridge was also freezing up and I overcame the problem by dowsing the unit in WD40 and leaving it for a couple of hours to soak in, the unit is a simple bi metalic operation which varies the temperature by varying the length of the control pin which is screwed in or out by the control knob. Once it had soaked I freed up the screw and operating arm and bellows by repeated operation. The unit was refitted and is operating at 100% with no problems.