An evaporator fan will turn on when the thermostat determines the temperature inside the unit is too high. The evaporator fan will not shut off until the correct temperature is reached. Blockages in front of the air vents in the freezer will prevent air from being drawn out of the unit. Move away any food packages that may block the vents. Check that the thermostat is set to the correct temperature as well.
The evaporator coils at the back of the unit, when blocked or dirty, will remain hot, causing the evaporator fan to run continuously. Pull the fridge out from the wall. The coils need to be a few inches away from the wall to prevent overheating that may cause the evaporator fan to run constantly. Vacuum the coils if they have dust on them. Again, dust may cause the coils to overheat a bit.
A faulty fan may run non-stop. The fan is located at the back of the freezer and is covered by the back panel of the unit. A freezer with an evaporator fan that constantly runs will have a build up of ice on the inside of the compartment. Unplug the freezer and allow it to thaw. Remove the screws from the panel and pull it off to access the fan.
Removing the Fan
The fan is held to the back of the freezer with a few screws. Remove the screws from the fan to release it from the back of the unit. Pull on the wire connectors with a pair of pliers to remove them from the fan. Remember where the wires plugged in. Obtain a new fan from GE, or take the fan to a parts shop. Plug in the new fan and close up the panel.