The 4 most common part(s) or condition(s) which cause the symptom Refrigerator not cold enough are listed below starting with the most likely. Check or test each item and watch any available videos.
If the refrigerator is not cold enough the condenser coils may be dirty. The condenser is like a radiator and must stay clean in order to dissipate the heat which was removed from the inside of the refrigerator. As the coils get dirtier the refrigerator becomes less efficient, which makes it work harder to cool down. If the coils are dirty enough, the unit will never be cold enough and will not be able to cool the inside of the refrigerator to the proper temperature.
RepairClinic Item # 221793
If the refrigerator is not cold enough, the evaporator fan motor might have failed. Every refrigerator has a set of coils called an evaporator. The refrigerator may have one or more evaporator fan motor(s) depending on the model and evaporator locations. The evaporator fan motor circulates the cold air from the coils thru the compartment. If there is only one evaporator it is in the freezer side. If the fan is not working, no cold air will get to the refrigerator compartment. The freezer may still get cold.
RepairClinic Item # 126964
If the refrigerator does not get cold enough the temperature control thermostat might be defective. The thermostat allows power to flow through to the compressor, evaporator fan and condenser fan. If the cooling system fans and compressor are running, but the refrigerator or freezer is not cooling correctly check for an airflow or defrost system problem.
RepairClinic Item # 1876189
If the refrigerator is not cold enough, the compressor might be defective. The compressor is a motor which compresses the refrigerant and circulates the refrigerant through the evaporator and condenser coils. There are several other components which are more likely to be defective if the compressor doesn't work. If the compressor itself is defective a licensed professional will need to replace it.