The cold air in your refrigerator comes from the evaporative coils located behind the freezer compartment. The refrigerator is a separate compartment, and cold air circulates between the two compartments through an opening.
A damper regulates the size of the opening, while a fan controls circulation. Both are monitored by a temperature-sensitive thermistor that tells the control panel when to open the damper and turn on the fan to achieve the desired temperature. If your refrigerator is freezing food and you even have vegetables freezing in refrigerator drawers, any of these parts could be the source of then problem with a refrigerator freezing food.
Before You Call Repair Technician
It's always possible that you've set the temperature control to a lower setting than you thought you did. To check, turn the control all the way off — which is the highest temperature setting — then gradually lower the temperature. At some point, you should hear a click, which tells you the control is probably working correctly. Move it a notch or two back to a higher setting — if it is working, your food should thaw.
If only some of the food in your refrigerator is frozen, it may because it's too close to the cooling coils. Try moving it to another part of the compartment that is farther from the freezer. If you have a freezer-on-top model, move the food to the bottom shelf. If it's a side-by-side model, move it to the side opposite the freezer.
Thermistor and Thermostat Problems
If the thermostat doesn't produce an audible click when you test it, it may be bad. The best way to determine this is to remove it and check it for continuity by applying a small current across it and measuring the resistance. The thermistor may also be bad; it's the temperature sensor that sends the signal to the main control panel when cooling is required. You can also test this part for continuity, although the procedure is a little more complicated.
Refrigerator Freezing Food Simple Test
To check the operation of the thermostat and thermistor, place a glass of water on one of the refrigerator shelves and put a thermometer in the water. Leave it there for several hours and check the temperature.
Adjust the controls to raise the temperature, then check back after another six hours. If the temperature hasn't changed, the thermistor or thermostat are probably faulty. Call a repair technician, who can check the parts for continuity.
Refrigerator Damper Problems
The damper regulates the amount of air that comes into the refrigerator from the freezer, and if it's stuck in the open position, the temperature in the refrigerator compartment will gradually become the same as that in the freezer. The damper is in a compartment in the corner of the refrigerator compartment closest to the freezer, and you may be able to unstick it by poking it with a pencil. If it it's broken, you can replace the whole damper assembly.
Main Control Panel
If the damper isn't stuck and the thermistor and thermostat are working, the problem is probably in the circuitry in the main control board. This type of problem isn't common, and it's difficult to diagnose. It's a job for a qualified service technician with the proper training and equipment.
Chris Deziel is a contractor, builder and general fix-it pro who has been active in the construction trades for 40 years. He has degrees in science and humanities and years of teaching experience. An avid craftsman and musician, Deziel began writing on home improvement topics in 2010. He worked as an expert consultant with eHow Now and Pro Referral -- a Home Depot site. A DIYer by nature, Deziel regularly shares tips and tricks for a better home and garden at Hunker.com.