To replace a refrigerator thermostat, unscrew its housing, disconnect the wires, extract the existing thermostat, push the new thermostat into the evaporator tube, connect the wires and adjust the refrigerator temperature. This process requires the refrigerator owners' manual, a flashlight, a screwdriver, needle nose pliers and a new thermostat.
Expose the thermostat
Consult the refrigerator owners' manual, and locate the thermostat. Unplug the refrigerator, unscrew the thermostat housing and set the cover aside. Illuminate the thermostat compartment with a flashlight. Locate the wire terminals, and use needle nose pliers to disconnect the thermostat from the wires.
Extract the thermostat
Unscrew the thermostat, gently pull it out of the evaporator tube, and discard it. If you have difficulty locating the screws, look for mounting clips, and open them to extract the thermostat.
Insert the new thermostat
Insert the new thermostat into the evaporator tube, and screw it in place. Pick up one of the refrigerator wires, and attach it to the thermostat with the pliers. Repeat with the other wire. Close the thermostat housing, and attach the cover.
Adjust the temperature
Plug in the refrigerator, and adjust its internal temperature control. An accurate change in temperature verifies that the new thermostat works properly.