If there is no cooling coming from your refrigerator, first check to see if the refrigerator light comes on. If you have no light, it may just be a faulty power cord or the cord has come unplugged. If the light is still on, check to make sure the thermostat is not off. If this checks out, you may have a failure with one of the refrigerator components, such as the compressor or the condenser fan.
To reach both the compressor and the condenser fan, get to the back of the refrigerator and remove the rear access panel. The compressor will be located behind a black box. This box comes off by removing a spring clip. Attached to the compressor will be a start relay and overload protector. Consult your appliance manual to find the exact location of these devices.
You will then use a multimeter to see if any of these components need to be replaced. A multimeter is a handheld tool that detects electrical current. Use the probes on the multimeter and take turns hooking them up to the start relay, the overload protector and the compressor itself. The overload protector should have a zero reading on the meter, while the start relay should read 20 to 100 ohms. The pin pairings on the compressor should have an infinity reading. Any other reading means the component needs to be replaced.
If the refrigerator is not cold enough, you may have dirty condenser coils or an obstruction in the condenser fan. The coils will be located in the bottom of the refrigerator. Unplug the refrigerator and remove the front and rear access panels. With a vacuum cleaner, clean out the bottom of the refrigerator without bending or disturbing the coils.
After cleaning the coils, remove the rear access panel to check the condenser fan. The fan will be located near the compressor. Check to see if there is anything that is stopping the fan from spinning. If no obstruction is present, you can use your multimeter again by attaching them to the fans leads. The meter should read between 50 and 200 ohms. Anything higher or an infinity reading means the fan is no longer working.
Too Much Cooling
To test for too much cooling, check the thermostat to see if it is too high or too low. If the thermostat is at the appropriate temperature, check to see if the thermostat is faulty. To do this, you will need to open the front access panel. On most models, the panel and thermostat will be located above the top shelf of the refrigerator. This panel can usually be removed with a few screws. Once the panel is removed, unscrew the control panel itself from the top of the refrigerator.
Locate the thermostat dial inside the control panel housing. Turn the dial to the coldest setting and attach your multimeter probes to the thermostat and look for a zero reading. Then take the themostat off, set to the warmest setting and place in the freezer for about 30 minutes. Then use the probes again, this time checking for an infinity reading. If these readings do not occur, your thermostat needs to be replaced.