Fridge Thermostat: What It Does, Why It Fails, and How to Fix It

When your fridge won’t stay cold, the fridge thermostat, a small device that controls the temperature inside your refrigerator by turning the compressor on and off. Also known as a temperature control, it’s one of the most overlooked parts in your kitchen — until your milk spoils and your ice cream turns to soup. This isn’t just about comfort. A broken thermostat can turn your fridge into a warm box, ruin food, and spike your electricity bill.

The compressor, the heart of your fridge that circulates refrigerant to cool the interior relies entirely on the thermostat to know when to run. If the thermostat sticks or misreads the temperature, the compressor either runs nonstop or never turns on. You might hear it humming constantly, or you might notice the inside is warm while the light still works. That’s not a power issue — it’s a thermostat problem. And yes, it’s often fixable without replacing the whole fridge.

Many people assume a fridge that’s not cooling means a failed compressor or a refrigerant leak. But in over 40% of cases, it’s just the thermostat. It’s cheap, easy to test, and usually costs less than £50 to replace. You don’t need to be an engineer — a multimeter and a bit of patience can tell you if it’s dead. The temperature sensor, the part that reads the internal air temperature and sends signals to the thermostat can also go bad, and it’s often confused with the thermostat itself. They work together, but they’re not the same thing.

Older fridges use mechanical thermostats with dials — those are simple and durable. Newer models use digital controls, which are more precise but harder to diagnose. If your fridge has a digital display and the temperature setting doesn’t match what’s inside, the issue could be the thermostat, the sensor, or even the control board. But before you panic and buy a new fridge, check the thermostat. It’s the most common reason a fridge stops cooling without making noise or showing error codes.

And here’s the thing: a bad thermostat doesn’t always mean a full replacement. Sometimes it just needs cleaning. Dust and grease build up around the sensor area, especially in older units. A quick wipe with a dry cloth can restore accuracy. If the dial is loose or the temperature keeps drifting, that’s a sign the internal spring or contact has worn out. That’s when you replace it.

You’ll find plenty of guides online telling you to check the condenser coils or the door seals first. Those matter — but if your fridge is running constantly and still warm, those aren’t the real culprits. The thermostat is the gatekeeper. It decides when the cooling starts and stops. If it’s broken, nothing else will fix the problem.

Below, you’ll find real-world fixes from people who’ve been there. From how to test your thermostat with a multimeter to which models are most prone to failure, and even when to call a pro instead of risking a DIY swap. No fluff. Just what actually works.