controlling temperatures in a side by side fridge

so the new digital thermostat is in route to my house (sweet!) and I plan to turn the extra fridge in the garage into a lagering fridge, but it's a side by side fridge. i will plug the fridge into to the thermostat and the thermostat into the wall, and run the thermostat probe into the fridge side, but nothing into the freezer side. any thoughts on what will happen to the temperature of the freezer? i am assuming it will go up, but will it be anywhere close to the side with the probe? or will it be closer to the outside temperature of the garage?

You freezer will cool faster than your fridge side. I would figure out what the temp difference is by setting the temp to lets say 50 deg and after the cooling period has stabilized, keep checking the freezer temp after every time the thermostat kicks your fridge on. You could always try to take out the divider wall or at least punch some holes in it as I bet there are lines running through it. This way you can keep both sides the same temp. Or you could also get two controllers and hook one up to the freezer and the other to the fridge? I dunno now I am just rambling....