My refrigerator is not cold but freezer is working fine cold air flows in fridge only when freezer door opens?

I have Kenmore top mount freezer refrigerator. My freezer is working fine but my refrigerator is not cooling. When i open my freezer door then the cool air starts flowing into my refrigerator but when i close it there is no air flow in my refrigerator. I cleaned and defrosted it and started it again but there is no change in its working.