Hi I bought a GE Eterna ESS25LSRB SS from a garage sale (not sure of the age completely) and the Fridge does not get cold enough. The previous owner said he had the fridge defrost on him recently and lost every thing in the Freezer. He then had to turn it up to 9 in the freezer and the refrigerator side to keep it cool but not very cold. I would like to service and use this refrigerator what are the first steps to find the problem. Thank you very much for your time and skills.