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Is your fridge thermostat not working, and you’re unsure about the reason?
Been there! Fridges are an essential part of our daily lives as they help keep our food fresh for longer and ready for consumption whenever we want.
I know how frustrating it can be to have your fridge thermostat fail – especially when you just bought your week’s groceries and are now worried about them spoiling. But don’t worry; you’ve come to the right place for answers. Below, you’ll find a list including 3 common causes behind a fridge thermostat that’s not working, as well as common signs of the problem.
Keep reading to get your fridge back to normal!
Craig has helped thousands of other homeowners repair their appliances since 2016.
Andy is one of our resident appliance repair experts with over a decade of experience. He currently runs his appliance repair company with a team of trusted technicians.
Common Signs of a Bad Fridge Thermostat
Although a bad fridge thermostat can manifest itself in many different ways, I’ve found that the most common signs of the problem are related to poor temperature regulation. You’ll notice the refrigerator is either too cold or too hot or not maintaining the expected temperatures.
Depending on your fridge’s brand and model, you might either have a cold control sensor or a regular temperature sensor. Cold controls are much more common in older models, whereas temperature sensors can be found in more modern appliances.
Cold Controls vs Temperature Sensors
Before diving into the actual causes of the problem, it’s important to understand the difference between fridge cold controls and temperature sensors.
- Cold Control: The Cold Control is a mechanical dial with metal tubing and gas inside it. It activates and deactivates based on the temperature that’s been dialed. As the temperature in the fridge increases, the gas pushes on a diaphragm that operates a switch responsible for turning the compressor on or off as needed.
- Temperature Sensor: A more modern approach. Unlike cold controls, temperature sensors can detect the temperature inside the fridge and activate/deactivate the compressor as needed. Since modern temperature sensors do not rely on a mechanical switch, they don’t wear out over time in the same way as cold controls do.
Diagnosing a Faulty Fridge Thermostat
Now that you know the main differences between cold controls and modern temperature sensors, let’s discuss the most common causes behind a fridge thermostat that’s not working so you can address the issue as soon as possible.
Here are some things to consider when getting started.
#1 The Cold Control Is Failing
If your refrigerator is an older model, there’s a good chance it still has a cold control to regulate the temperature inside it. Since cold controls are mechanical and rely on physical switches to turn the compressor on and off, having them break over time is not uncommon.
If your fridge thermostat is not working and the temperature inside the appliance seems to be fluctuating too much or not reaching the levels you’ve dialed in, you’ll have to take a closer look at the component.
Solution: To diagnose whether a faulty cold control is causing your problem, you’ll have to bypass the component, which, in my experience, is very easy. Here’s what you have to do.
To access the Cold Control:
- Open your fridge door and remove the cold control cover by removing the screws holding it in place. Please refer to your User Manual for a clearer idea of where the cover is.
- Once the cover is removed, you’ll have a clear view of the damper assembly and the Cold Control.
- In many fridge models, there will also be a control panel section with dials that you’ll also have to remove by undoing a set of screws; otherwise, the cold control cannot be exposed properly.
- You should now be able to see the Cold Control clearly.
To bypass and replace the Cold Control:
- Take a picture of the wiring for reference, and unplug the faulty Cold Control.
- The Cold Control typically has 2 main connections. Locate them and put a jumper cable between them to bypass the Cold Control.
- Plug your fridge back into the wall outlet or restore power from your circuit breakers and see if it works normally (please do not touch any wires or components at this time, as you risk electrocution. Just observe how the fridge works).
- If you notice the fridge works normally with the Cold Control bypassed, you have confirmation that the component is faulty.
- Unplug your fridge from the wall again or cut off power to the appliance from your circuit breakers, and remove the jumper cable afterward.
- Buy a new Cold Control to replace the faulty one you just removed. You’ll need your fridge’s model number and your User Manual to find the right part model number for the replacement.
Once you have the new Cold Control and with the fridge still unplugged, install the component, plug the cables back in, and reassemble the covers.
Typically, replacing a fridge’s Cold Control is more expensive than replacing a modern temperature sensor, so weigh your options carefully. If your fridge is already very old and due for replacement, I find it’s not the best idea to spend more money on a new Cold Control.
#2 The Temperature Sensor Is Faulty
If your fridge doesn’t have a Cold Control, the most likely reason why the thermostat isn’t working is that the temperature sensor is faulty. The temperature sensor inside your fridge fulfills a similar purpose to the Cold Control in older models. However, the main difference is that modern sensors do not rely on gas and physical switches to work, which makes them more durable.
Modern fridge temperature sensors work hand in hand with the appliance’s Control Board, which is, in a nutshell, the unit’s brain. The Control Board inside your fridge is responsible for processing your inputs and allowing all the other components inside the appliance to communicate and work with each other.
When the temperature sensor is faulty, it sends false signals to the Control Board, prompting it to activate or deactivate the compressor and regulate the fridge’s internal temperature incorrectly.
The temperature sensor and the Control Board communicate via Ohms resistance. Different resistances mean different temperatures.
Solution: To address the situation, you’ll need a multimeter and some knowledge about Ohms and resistances. But before you go and check the more complex aspects of a faulty temperature sensor, I recommend you also look at the wires connecting the sensor to the Control Board and ensure they aren’t damaged.
If you followed the steps from the previous point, you already have access to your fridge’s temperature sensor and Control Board. Inspect the wiring, and once you’re sure it’s undamaged, my usual advice is to take your multimeter, set different temperatures on the fridge, and test the resistance of each one.
You should see the resistance readings change as you adjust the temperature settings. However, you’ll need to replace the temperature sensor if you don’t notice changes or the readings are erratic. Luckily, modern fridge temperature sensors are simple and cheap to replace.
That said, if you’re not sure about the replacement or resting process, please contact a professional for help.
#3 The Control Board Needs Replacing
The last possible reason why your fridge’s thermostat is not working is a bad Control Board. As I mentioned earlier, the Control Board is one of the most important parts of a fridge, as it helps all other components communicate and work together.
If you’ve already replaced the temperature sensor on your fridge and you’re still having issues, there’s a good chance that the Control Board itself is reading the sensor’s signals wrong.
Solution: Since fridge Control Boards are more complex than Cold Controls or temperature sensors, my usual advice is to leave the testing and diagnosing to a certified technician. Control Boards are not typically cheap, so you’ll have to weigh your options and determine whether replacing yours is the most cost-effective solution.
Estimated Cost of Repairs
The cost of repairing your fridge’s Cold Control/Temperature sensor will vary greatly depending on the appliance’s brand and model, the availability of the parts, and whether you want to call a technician to your home to do the installation. That said, I can give you a ballpark estimate of the cost of the parts based on average data.
- Cold Control: Cold Controls start at around $50; however, the replacement can be much more expensive if you own a high-end model.
- Temperature Sensor: starting at $20, but similar to the Cold Control, the price can skyrocket depending on your fridge’s brand and model.
- Control Board: The most expensive part to replace. Lower-end fridges can get a Control Board replacement for around $100, whereas higher-end ones can cost $800+.
While calling a professional can simplify the replacement process and keep you safe from electrocution and other hazards, please remember that getting a technician to do the repair can increase costs from $100-$200 on average. At the end of the day, it’s a judgment call and a budget-related decision.
Can Your Warranty Cover the Part Replacement?
It depends. For Cold Controls, I sincerely doubt it. As I’ve said before, Cold Controls are much more common in older refrigerators, which will likely be outside the normal refrigerator warranty period most manufacturers will offer.
Temperature sensors, on the other hand, may still be applicable for free replacement if the failure originates from factory defects rather than improper use of the appliance. My usual advice is to know for sure is to either contact your manufacturer directly or check your warranty policy to see the document’s specific terms and conditions.
Fixing a Fridge Thermostat That’s Not Working
That about covers it! When your fridge thermostat isn’t working, you can quickly worry about your groceries spoiling.
Luckily, as I hope this piece has helped you better understand, addressing the most common causes behind a fridge thermostat that’s not working can be easy, quick, and cheap. More often than not, something as simple as replacing the Cold Control will do the trick.
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Have a wonderful day!