Some do-it-yourselfers can fix the temperature control if it’s accessible. To find out whether yours is, take the front panel off the control panel. You will see a small oval or cylindrical copper tube with a sensor bulb on one end. (The tube might be a few inches to a couple of feet long, depending on the model and make of the refrigerator.) If you can see all of tube, you can replace it and fix the control. If it leads into a side wall and hides there, forget it; there’s nothing you can do. For those who have accessible controls, follow these steps:
Unplug the refrigerator.
Mark the wires so you know where they go into the switch.
Take out the switch and tube.
Go to an appliance parts store with the switch and tube and the model and serial number of the refrigerator and get a new part.
Do not kink, bend, or fold the new tube as you carry it home or install it. Doing so will permanently damage it because there’s liquid inside the tube.
Put the new tube into the refrigerator just as the old one was installed with either push-on clips or wires that have to be screwed together.
Screw the panel onto the control housing.