I use a Johnson Controls Digital Thermostat Control Unit. I bought it through Amazon.com for around $75. There is a non-digital version for around $59. It works well, I have no complaints. Periodically I check it and so far the temperature has been in range. You plug the controller into the wall and the refrigerator into the controller. There is a sensor you put inside the refrigerator and close the door. Good luck, and I would love to hear what you decide to do and how it worked out.