Refrigerator/Freezer runs constantly

I have a Kenmore Elite side by side refrigerator/freezer. It appears that the appliance does not shut off and runs constantly. The freezer is set to 0 and the refrigerator set to 37. Freezer is keeping food and ice frozen and refrigerator keeping food cold. Seems like it is the freezer fan is what is running constantly but not absolutely certain. Any ideas and any suggestions greatly appreciated. We bought this unit after Hurricane Katrina on 10/19/2005 so it is not that old.
Thanks,
Glenn