How to Troubleshoot a Refrigerator Thermostat

Have you ever looked in your refrigerator for something to make for dinner, only to find that everything inside is frozen? Or, perhaps when you go to pour the milk on your cereal, the milk flows out with accompanying icebergs? If you have, then there may be a problem with your refrigerator's thermostat.

Many people make the mistake of purchasing a new refrigerator at the first sign of trouble with their current one. This is costly and often times, unnecessary. In many cases, a little troubleshooting can save you a ton of time and money. Here is how to troubleshoot your refrigerator's thermostat.

Difficulty: Moderate

Instructions

Things You'll Need:

• Screwdriver
• Volt-Ohm Multi-tester
• Notebook
• Pencil
• Flashlight

1. Check the easiest and most common potential causes first, which is the best course of action in any troubleshooting case. With a freezing refrigerator, this means checking the thermostat itself to see if it is set at the right temperature.
   
   Sometimes, other family members may accidentally turn the dial, so just make sure that the dial is not turned to the coldest setting. If the setting is correct and you are still having your foods frozen, then you may have to troubleshoot the workings of the thermostat.

2. Unplug your refrigerator. Next, locate the control panel where the thermostat is located and remove all of the items near it so you can work.
   
   The thermostat is located directly behind the dial. You may need the flashlight to help you see inside the refrigerator.

3. Remove the plastic cover that protects the controls. Some covers are screwed into place while others are held in place by plastic clips. Depending on your make and model refrigerator, you may have to first remove the dial before you can take the cover off.

4. Turn the dial to the coldest setting. Remove the two leads (wires) on the thermostat.
   
   Note: It helps to write down which lead goes where for when it's time to replace everything.

5. Set the volt-ohm multimeter to RX1 and probe the terminals. By "probe," I mean touch one of the multimeter's probes to one terminal on the thermostat and the other probe to the other terminal.
   
   You should be getting a reading of zero. If you get a zero reading, then move on to Step 6. If you do not get a zero reading, then remove the thermostat and take it to an appliance store for a replacement.

6. Remove the thermostat from the refrigerator entirely. Set the dial on the thermostat to the warmest setting and place the thermostat in a working freezer for 30 minutes.
   
   After the 30 minutes are up, reprobe the terminals and look for a reading of infinity. If you get the infinity reading, then the thermostat is fine. Simply reinstall it, plug the refrigerator back in and look for another cause of your freezing problem, like dirty coils.
   
   If you do not get an infinity reading (sideways "eight"), you should replace the thermostat with a new one.

[shamrock737]

on 8/14/2008 Thanks. I was using the correct setting. I still read zero (not infinity) after freezing so I'm off to get a new thermostat. I appreciate your help!

[davedonovan]

on 8/14/2008 Hi Shamrock737,

All multi-meters are different, but most label their ohms setting as RX1 or X1. It may also have a sign that looks like an "O" with feet, or it may just say "Ohms." That is the setting you will want to set it to. If the fridge is running warm, double check that nothing is blocking the vents inside the fridge. They are located in the rear of the compartment. Sometimes a ziploc bag can get stuck in front of them and restrict the airflow. If that isn't the problem, double check the thermostat setting and vaccuum off the coils. If still no lick, then odds are it's your thermostat going bad. Good luck!

[shamrock737]

on 8/14/2008 What is the RX-1 setting? My meter does not have that position. Also my refrigerator is running too warm not freezing everything...is thermostat still a good guess?