If a refrigerator doesn't cool at all, the problem is often with the basic electrical controls—almost never with a need for a boost of refrigerant.
Do not assume the problem is related to the compressor or the sealed, hermetic system; these types of problems happen only rarely. Your unit may have dirty condenser coils, a door that doesn't seal tightly, or a defective temperature control.
1) Check the cold control. Be sure it is set to "cold." Normally, the temperature inside the refrigerator should be about 37 degrees Fahrenheit.
2) Listen for the freezer fan inside the freezer. When the freezer fan is running, it means the defrost timer and the cold control in the refrigerator are both set to cool.
3) Listen for the compressor fan, where the compressor is located (typically behind or beneath the refrigerator. When the freezer fan is operating, the compressor fan should also be working (most of the time).
4) If one of the fans is not working or the compressor is off, the refrigerator will offer very little cooling or none at all. Call an appliance repairperson.
