The temperature in the refigerator section will not go below 42 F. I replaced the defrost controller 6 months ago and the freezer coils are not currently blocked with ice, so it can’t be the controller or heater/thermastat. What else would be limiting the cooling air into the refrigerator and how do I fix it. Thanks.
Here are your parts
http://www.appliancepartspros.com/partsearch/modelsearch.aspx?model=JCD2289AEB
Is the compressor cycling correctly?
Is the freezer temperature OK. You may want to check this with a thermometer.
Is the evaporator fan running? It is required to push the cold air into the fresh food side.
Is the lower vent clear? Although the parts breakdown does not show a frame drawing their is usually a vent towards the bottom of the fresh food/freezer sides that must be left clear for proper air circulation.
Is the damper (Item 8 in Section 2) door open? This controls the amount of cold air that enters the fresh food side. Could be something as simple as the spring (upper right corner of picture) coming off.
Click on the picture for better/more views of the parts.