It sounds as if your refrigerator has stopped automatic defrosting of the evaporator coil or has a plugged defrost drain.. Below is some information provided by: www.repairclinic.com
, to help you understand what may be wrong with your unit. If it is not cooling properly, you may be able to get it cooling again, temporarily by removing all perishable items, unplugging the unit, and allowing it to stand idle wth the doors open. This will allow the ice to melt, which will allow air flow to resume normally through the unit. Allow several hours for the ice to thaw completely, then close the doors and return it to an operational status. Put water in both compartments and when satisfied with the results of temperature, i.e. frozen in freezer and cold in fresh food compartment, you can put perishables back in. This will allow normal operation for only about a week until the defective part gets replaced, then it will start warming up again.
If the drain is plugged then the diagrams should show the routing so you can clean it out.
Today, all but the smaller, apartment-sized refrigerators are self-defrosting. Self-defrosting means what it implies--though frost continues to accumulate inside the refrigerator, it melts automatically. The self-defrosting system has three functional components: Defrost timerDefrost heaterDefrost thermostat.
The timer is like a clock. It continually advances, 24 hours a day. Every 6 to 8 hours, the timer turns off the cooling system of the refrigerator and turns on the defrost heater.
The defrost heater is similar to the burners on an electric stove. It's located just beneath the cooling coils, which are concealed behind a panel in the freezer compartment. The heater gets hot. And, because it's close to the cooling coils, any ice or frost build-up melts.
As the frost and ice melt, the resulting water drips into a trough. The trough is connected to a tube that drains the water into a shallow pan at the bottom of the refrigerator. The water is then evaporated by a fan that blows warm air from the compressor motor over the pan and out the front of the refrigerator.
The process ends after either the amount of time specified on the timer or when the defrost thermostat near the cooling coils senses that the heat near the coils has reached a specific temperature.
Detailed parts diagram: