First, check the fan motor for dust or debris that may be hindering its normal operation, and if that does not seem present, then proceed to replacing it. Make sure the refrigerator is unplugged, and then remove the wiring from the fan motor and unscrew the motor from the appliance.
A new fan and motor must be assembled before it can be installed into the refrigerator. Do this before replacing your old fan motor. When installing the new fan motor, make sure the wires are placed in the same positions as before, otherwise the fan motor will not function correctly. Only screw in the fan motor completely when this has been determined. Once it has been installed, check for correct fan rotation to ensure air flow is moving the right way. Then replace the refrigerator where it was, as the fan motor has been properly installed.
The fan motor in a refrigerator circulates air in the appliance. Without this fan, some areas within a refrigerator would be different temperatures, leading to some food not being properly cooled. This is the same case as with freezer fans, and even leads to frost burnt food or melting if the fan is not functioning correctly.