I use this [analog thermostat][1] from Johnson with my keezer. (No affiliation with Rebel. Just like them personally.)

Doesn't require any splicing/wiring. Very convenient. Just need to run the temperature probe into the freezer somehow. (I have a collar on mine, so it works perfectly.)


  [1]: http://www.rebelbrewer.com/shoppingcart/products/Refrigerator-Thermostat.html