I have a frig model 3639656686 the freezer works great. the frig stays warm. I have replaced the control and stat for the self defrosting unit the only other thing is the heater. The coil part will freeze over solid and than no cooling of frig

Hello,
A refrigerator not cold enough is a hassle, because you are at risk of spoiling the foods you store in there. Most often, this problem is caused by something easy to fix. 1. Faulty Door Gaskets
The door gaskets in a refrigerator ensure a sealed closure every time you shut the door. Torn or loose gaskets on the door of the refrigerator can result in a leak in the cold air. As a result, the refrigerator is warmer. Repetitive and frequent opening and closing of the refrigerator is also a possible cause, because the warm air from outside replaces the cold air in the refrigerator every time you open it. 2. Dirty Condenser Coils
Dirty condenser coils can result in improper functioning of the refrigerator. These coils are located on the back or the underside of refrigerators. If you find this to be the cause of the problem, unplug the refrigerator before you attempt any cleaning. 3. Frost-free Feature not Working
If the frost-free feature fails, it causes a buildup of frost around the evaporator coils in the freezer. This causes a malfunctioning of the evaporator fan that blows cold air around. The fan can also be damaged if it hits the frost. 4. Faulty or Incorrect Temperature Control
A faulty thermostat can lead to a refrigerator that is not maintaining the desired coldness. Check for this problem and also ensure that the temperature is set to the correct level. Normally, refrigerators are set to a temperature of about 0°C, whereas the freezer sections are around -17°C. 5. Inadequate Air Flow inside Refrigerator
A refrigerator that is loaded with too many food items can fail to maintain an adequate level of coolness across all the items kept in it. The surface items tend to be colder, and the items underneath do not become as cold. A refrigerator that has very few items in it can also fail to function efficiently. Try to ensure that your refrigerator has enough food in it at all times, but is not so loaded that the air flow gets constricted. 6. Vents between Freezer and Refrigerator Clogged
The vents between the freezer and refrigerating section blow cold air from the freezer across to the refrigerator. If these vents are clogged with ice, the air is blocked and the refrigerator does not cool down. If this is the case, you can unplug the refrigerator, wait for the ice to melt and then connect it back to the power supply. 7. Faulty Door Switch
The door switch is found on the bottom of refrigerator doors. It turns off the light in the refrigerator and resumes cooling action when you close the door. If this switch is not functioning properly, the refrigerator will not be cold and it will also be affected by the heat of the interior light. 8. Refrigerant Leak
A refrigerant leak is very unlikely. This problem can cause malfunctioning of your refrigerator. If you suspect this to be the cause, contact a service technician.
Hope this will help out....