Two weeks ago my refrigerator was not cooling and freezer was cold on bottom and not on top. Did some searching on the web and found that my fan was running and the condenser worked. Removed all food and saw coils had frost build up. Used blow dryer to defrost and left unplugged for about 3 hours. Next morning turned on and it was working again.
Well here we go again, same thing happening. What is causing this to do happen?
Thanks for any help

You have a defrost problem. Check the defrost element to see if it is broken using an Ohm meter. If there is continuity then check the defrost thermostat with your Ohm meter(must be cold to be closed so check before you defrost) If thoes two are good then replace the timer. As always when using your Ohm meter make sure your fridge is turned off or even better unplugged.