admiral ltf2112arw not cooling bottom portion?

i have an admiral ltf 2112arw that the refrigerator portion is not cooling. I cleared the dust out of the back, I opened the freezer portion to get to the evaporator and there werent any significant ice build up. I removed the little ice that was blocking the passage way to the refigerator part. I also noticed that the fan in the freezer was not coming on. what can be the problem?