freezer and Fridge not cooling

Hey, need help my Fridge and Freezer are not cooling/Freezing. I just changed the defrost timer and its turning off and defrosting like its supposed to. It will still frost up some but defrost off. So my ? is why is it still not cooling? what could it be? Is it maybe because there is no fan for the compressor or does this model Fridge not have one? Please help:confused: