The 1 most common part(s) or condition(s) which cause the symptom Refrigerator runs constantly are listed below starting with the most likely. Check or test each item and watch any available videos.
If the refrigerator runs constantly check the temperature of the freezer. If the freezer temperature is above 10 degrees F. (-12C) and cannot achieve a colder temperature it may run constantly. This is usually a sign of frosted over evaporator coil. (not defrosting properly) a worn out compressor, Refrigerant leak, dirty condenser coils, a slow condenser fan motor or bad door seals. The freezer should be able to maintain between 0 and five degrees F. (-18 to -15C) and still cycle on and off at regular intervals. If all the functional parts are working remove the evaporator cover and look at the frost pattern on the coil. If you are only getting half frosted you may have a refrigerant leak and will need to call for service. This may be an expensive repair.