refrigerator coil frozen up and kept the refrigerator from cooling

Remove front cover below door, remove 2 screws attaching the defrost timer to the refrigerator frame.
Unplug wiring harness plug from timer an install new one.
Remove metal cover in back of the freezer compartment. unpug the two wires going to the thermostat, remove the thermostat { thermostat is held onto the cooling coil with a clip} , remove thermostat and replace with new one