Kitchen aid frig not cold. Hi,Refrigerator suddenly not getting cold. Pull out Freezer on bottom

Question

Hi,Refrigerator suddenly not getting cold. Pull out Freezer on bottom works fine.We had a issue a couple of times in the past where it would stop working for a day, I would turn the switch on top off and on and then it would start working again. This time the switch is not helping. It has not been cleaned since we bought it in 2004. I hear the fan uptop working. Any ideas?