Test the T'stat
You can tet the thermostat with a glass of ice, water and a thermometer.Carefully insert the thermostat sensor tube in the glass of ice water. You should be able to rotate the setting knob back and forth and feel the contact click in and out. Also, you can test the thermostat by turning off the power, removing the leads from the terminal strip and using a continuity meter. (Have someone rotate the knob)The temperature of the water should between about 35 and 45 F. You can control it by adding more water or ice.If everything seems to be working with the thermostat, you must insure that the fan is actually cycling on and off with the setpoint of the thermostat.Our 376 had the same problem. The refrigerator fan was wired to the board and it ran constantly, causing freezing.I traced out the thermostat lines and made the correction and it now works fine. The power from the terminal must go to the thermostat, then back to the power leg of the fan and the other side of the fan pwer lead to the ground. (wiring diagram with documentation)If the refrigerator fan is cycling okay with the thermostat, check that the freezer 'stat is cycling the compressor on and off. Also, if the freezer is set way too cold, it could lead to a frozen 'fridge compartment.If all of this is functioning properly, damper down the opening between the freezer and the 'fridge that does NOT have the fan. Do this in small increments. Too much dampering could possible cause the fan to fail. About 50% should be the maximum. To damper the opening use a cutout piece of a plastic water bottle to make the opening smaller. This will cut down on the air circulation between the compartments therby raising the temperature of the 'fridge.Good Luck,Mike D.