If a refrigerator is no longer getting cold, there may be several problems to blame, including a lack of electricity, a problem with the cooling controls, a fan that is not working in the freezer section or other bizarre problems with parts. Try resolving the problem with one of these techniques; if the problem will not resolve, then call in a service person to perform diagnostics.
Many times, when a refrigerator is not cooling properly, it is due to a lack of electricity. Children will move the refrigerator to get a toy hidden underneath or a housekeeper might move it to clean the area behind it. Check to see that the refrigerator is plugged in fully.
Another common problem is with the cooling controls. Cooling controls can easily be turned off by accident when putting food in and taking food out of the refrigerator. The cooling unit can also have problems with its thermometer gauge, which can then lead to problems with cooling the entire refrigerator unit. Thermometer problems will need to be fixed with parts and a repairman.
If a fan isn't working in the freezer section, then the cooling apparatus will not work within the refrigerator. When opening the freezer section, there should be an audible sound of the air moving. The switch should also be on.