Your refrigerator uses a heat pump to cool the food inside. A heat pump transfers the warm air from inside of the refrigerator to the outside of the refrigerator through the condenser coils. In effect, your refrigerator removes heat from the items inside as opposed to cooling them. There are several components to troubleshoot when the refrigerator stops cooling. Cooling problems for a refrigerator can mean a serious expense if the problem is major and may require the services of a professional.
Check the temperature setting inside the refrigerator and set it to a colder setting if necessary. Sometimes the temperature button is accidentally switched. Listen for the compressor to turn on when turning the temperature control up and down. If it doesn't you may have a condenser problem, and should contact a service professional.
Move food containers away from the vents on the inside of the refrigerator. Food containers may block the removal of heat from the fridge.
Pull the refrigerator out from the wall and inspect the coils for bends or excessive amounts of dirt. Unplug the refrigerator and vacuum the refrigerator coils using a soft brush attachment to remove any dirt.
Remove the front grill of the machine and look underneath for dust. Vacuum out any dirt or dust. In some new refrigerators the condenser coils are located underneath the fridge.
Unscrew the cover panel from the back of the fridge using a screwdriver and remove the panel. Inspect the condenser fan for dust build-up. Vacuum the condenser fan to remove the dirt which may block it from moving.
Open the fridge door and inspect the rubber gasket running around the door for cracks. A cracked gasket may let out too much cold air. Lift up the lower flange of the gasket, if cracked, and loosen the screw holding the gasket down. Do not remove the screws. Take the gasket to a hardware store for a replacement. Press the new gasket in place and screw down again.