Fermenting Fridge

[Riggers]

I have recently purchased a Westinghouse Aurora Moist Cold Cyclic Defrost "upside down" fridge freezer (i.e. freezer below fridge on top)
I intend to use it for a fermenting fridge but I want the freezer to work independently of the fridge so the freezer remains as a freezer irrespective of the temperature of the fridge compartment. I want to fit an electronic digital temperature controller for the fridge compartment for obvious reasons.
A "frigemate" type controller is obviously no good because it simply cuts the power to the whole unit and of course the freezer will turn on and off as well - not what I want to achieve.
Ordinarily a fridge thermostat is a simple switch mechanism but the one in this fridge seems a bit more complicated. It has 3 connectors on it, one is power in, one is for the compressor and the other is a bit of a mystery. I suspect the mystery wire drives a defrost timer and/or thermostat but I'm not sure, I have been unable to confidently ascertain what it is.

Is there a fridge technician out there that can help?

 

[mika]

The freezer will be on the same cooling circuit as the fridge, unless it's one of the rare versions with two compressors. If it's a single compressor I can't see how you could control the temps independent of each other.
If it is a two compressor unit it should be simple enough to track the wires down to the compressor for each compartment and bingo bango, there ya go.
Rest assured that if your fridge is set to do 12C, the freezer compartment will be freezing stuff. Even at 18C in the fridge, it's frickin' cold in the freezer.