The Fridge is in a house I am about to buy and would like to know the basic troubleshooting steps to take. The Freezer will freeze items on the bottom half of the freezer and the bottom half of the fridge will be fairly cool probably in the correct storage temperature range but the top of the fridge and freezer are not at the correct temperature. The condenser coil and back panel had some frost build up so I unplugged the Fridge for 24 - 36 hours so it could thaw out. I also cleaned and vacuumed up the dust on and around the compressor and fan on the back bottom of the fridge. When I plugged the freezer back in it seemed to semi freeze a bag of water in the top of the freezer but it wasn't cold enough to completely freeze the bag. I waited 48 hours to check on the freezer.

I have read that the defrost timer may be bad but I'm not sure where to start to test the components of the fridge. I am very handy and can obtain most of the testers that would be be needed.

Thank You.