I recently picked up a newer GE side by side fridge to replace my old chest freezer that died. I wanted to turn the freezer side into a kegerator and the fridge side for fermenting ales, so I knew that I would need to replace/override the factory thermostats to make things work.
I looked inside before i bought it and saw it had dial knobs for the thermostats so I thought I would be good to go with the standard method of replacing the mechanical thermostats with digital ones. I bought two STC-1000s from ebay and started checking out the wiring while I was waiting for the thermos to arrive. Once I opened up the panel with the thermostat knobs, I saw they are connected to a small circuit board and have 6 wires connected to it. I found out that these knobs are connected to digital rotary encoders. They send some sort of pulse signal back to the main control board to indicate the position of the knob. Unfortunately, I could not find a way to jump the incoming power line directly back to the board to turn the fridge on and off. I probably could have built a small square wave generator with a timing chip but it didn't seem like it was worth it.
So I found the wiring diagram and starting poking around the main board, the compressor and condenser area, and the evaporator. My new plan was to cut into the compressor and fan power between the main control board and the devices. Since I would be leaving the factory thermostats in place, the control board would always be trying to cool the fridge and freezer, and I could use the STC-1000s to disconnect and reconnect power as needed. To complicate things, this particular GE fridge uses 120VAC for the compressor and 13VDC for the condenser and evaporator fans.
I ended up using a two pole relay to switch the 13VDC to the condenser fan and the 120VAC to the compressor. This relay is controlled by the STC-1000 that monitors the freezer temp. I left the evaporator fan connected and running all the time to provide circulation and even temperature distribution for the kegs.
I mounted the STC-1000s in the fridge door and tapped into the interior light for power. Right now I am using 3 60mm AC box fan but can only get the fridge side down to 45°F when the freezer is at 35°F. I plan to replace them with 2 120mm AC fans to enable better crash cooling.
I used a piece of stainless steel sheet metal to cover the hole where the ice dispenser used to be. I found a guy on ebay, he even cut it to the size I needed for free. I used a piece of plywood behind the sheet metal for reinforcement and installed my 4 taps,
I still need to add a shelf in the freezer to get a second layer of kegs in there but I only have one beer kegged right now so its not urgent. I am so glad that I can keg now and don't have to wash a bunch of bottles.
I know some other people here are working on similar projects, if you have any questions feel free to ask.