If the refrigerator isn't cool, check to see if the light comes on when you open the door. Next check to see if the thermostat is set properly. If both of these are OK, then check to see if the compressor is running.

See if the compressor motor is running. The compressor is in a case with no visible moving parts. It is usually located at the back of the refrigerator near the bottom. If it’s humming, or making a steady noise, and your refrigerator is still not cooling properly, there could be a problem with one or more various components.

Refrigerators have either a mechanical defrost timer, or an ADC (Adaptive Defrost Control). If your refrigerator has a mechanical timer, set the cold control to the coldest setting and then advance the defrost timer. You can manually advance the timer with a screwdriver. Insert the screwdriver into the advancement pinion and turn clockwise a 1/4 to 3/8’s of a turn. If the compressor starts, replace the defrost timer. For further help, you’ll want to call a professional appliance repair technician.

Sometimes you can hear a click-buzz-click sound coming from the compressor. This is the relay/overload at work. If you hear this, power is getting to the compressor. If you do, something is wrong with either the compressor or the compressor starting components. If you have a newer model with solid-state starting components, you may not hear anything at all. If there is power to the starting components, you may be able to test each part and replace any bad parts. There is also a 3-in-1 unit that may work on your model which replaces all the components in one unit. If the compressor still won’t start, you have a bad compressor and need to replace it. If it does start, wire the 3-in-1 part in permanently. Make sure the one you buy is rated for the horsepower of your appliance.

If you don’t hear anything, you can take the cover off the side of the compressor and test for voltage at the two leads. If no voltage is present, it’s time to check the cold control. To test if the cold control is bad, you can temporarily jump the two wires at the cold control. If you get power to the compressor after doing so, the cold control needs to be replaced.