What a temperature sensor does and why it fails

A temperature sensor (also called a thermistor or RTD probe) measures the heat inside your oven or refrigerator and tells the control board what temperature the appliance has reached. When it fails, your appliance either won't heat or cool at all, heats or cools unevenly, or displays an error code. The sensor itself is a small metal probe, usually 2 to 4 inches long, that screws or clips into the wall of the cooking or cooling chamber.

Temperature sensors fail because they age, get damaged by food spills or moisture, or straightforward stop responding to heat changes after years of use. Unlike a heating element or compressor, a sensor cannot be cleaned or reset—once it stops working, replacement is the only fix. The good news is that replacing one takes 15 to 30 minutes and costs $15 to $60 for the part itself, depending on your appliance brand.

Key Takeaways

  • Unplug your appliance before you start, and wait at least 5 minutes for any residual power to drain from the control board.
  • Write down the exact model number from the nameplate on the back or inside your appliance, then order the correct sensor online or from the manufacturer's parts line.
  • The sensor is usually held in place by one screw or a spring clip, and the wire connector pulls straight out once you remove the fastener.
  • Push the new sensor in firmly until it seats completely, reconnect the wire, and screw or clip it down before plugging the appliance back in.
  • If your appliance still shows an error code after replacement, the control board itself may be faulty, and you will need a technician.

Find your model number and order the correct part

Before you open your appliance, locate the model number on the nameplate. On most ovens, this is on a sticker inside the oven cavity, usually on the left or right wall near the top. On refrigerators, it is typically on the back wall inside the fridge compartment or on the back exterior panel. Write the full model number down—it usually starts with letters (like GE, LG, or Whirlpool) followed by numbers.

Call the manufacturer's parts line or search their website with your model number and the words "temperature sensor" or "oven sensor." You can also search online parts retailers like PartSelect, AppliancePartsPros, or Sears Parts Direct. Order the exact sensor for your model—do not assume two sensors are interchangeable just because they look similar. The connector type and resistance range must match, or the new sensor will not communicate with your control board.

Unplug the appliance and locate the sensor

Unplug your oven or refrigerator from the wall outlet. Wait at least 5 minutes. This drains residual power from the control board and prevents accidental shock or damage to the electronics. Even though the appliance is off, electricity can remain stored in capacitors on the board.

For an oven, the sensor is usually mounted on the left or right interior wall, roughly in the middle of the cavity. It looks like a thin metal rod or probe sticking out from the wall. For a refrigerator, it is typically on the back wall of the fridge compartment or inside the freezer section, depending on the model. If you cannot see it, check your user manual or search online for "[your model number] sensor location"—many manufacturers post diagrams.

Remove the old sensor

Once you locate the sensor, look at how it is fastened. Most sensors are held in place by a single screw or a spring clip. If it is a screw, use a Phillips or flathead screwdriver (whichever fits) to remove it. If it is a clip, gently pry the clip away from the sensor probe with a flathead screwdriver or your fingernail—do not force it, as the clip can break.

After you remove the fastener, gently pull the sensor straight out of the wall. You will see a wire connector attached to the back of the sensor. Pinch the connector clip (usually a small plastic tab on the side) and pull the connector straight away from the sensor. Do not yank the wire itself, as you can damage the internal wires. Set the old sensor aside.

Install the new sensor

Before you insert the new sensor, inspect the hole in the appliance wall. If there is any food debris, grease, or moisture, wipe it out with a dry cloth. A clean hole ensures the sensor sits flush and makes good contact with the appliance interior.

Take the new sensor and align it with the hole. Push it in slowly and steadily until it is fully seated—you should feel it stop when it reaches the back of the hole. Do not force it; if it meets resistance, pull it out and check that the probe is straight and not bent. Once the sensor is fully inserted, reattach the wire connector by pushing it onto the sensor terminal until you hear or feel a click. The connector should not slide off if you tug gently on the wire.

Now find the sensor with the screw or clip. If it is a screw, tighten it firmly but do not over-tighten, as you can crack the sensor or strip the hole. If it is a clip, push it back into place until it holds the sensor snugly. The sensor should not wiggle or move when you gently try to push it.

Test the appliance and troubleshoot

Plug the appliance back in and turn it on. For an oven, set it to 350°F and listen for the heating element to click on within 30 seconds. The oven should begin to heat, and the temperature display should start to climb. For a refrigerator, set it to 37°F and listen for the compressor to start within a minute or two. The fridge should begin to cool.

Wait 10 to 15 minutes and check that the temperature is rising (oven) or dropping (fridge) steadily. If the appliance heats or cools normally and no error code appears, the replacement was successful. If an error code still appears, or if the appliance does not heat or cool, the control board itself may be faulty. In that case, you will need a technician to diagnose and replace the board, as that is beyond a home repair.

Common mistakes to avoid

The most common mistake is ordering the wrong sensor. Always use your exact model number, not a similar-looking model. A sensor with the wrong resistance range will cause the appliance to misread the temperature, even if it physically fits.

The second mistake is not waiting long enough after unplugging. Touching the control board while it still has power can damage it or injure you. Always wait at least 5 minutes. The third mistake is forcing the sensor into the hole or over-tightening the screw. The sensor probe is fragile, and excessive force can crack it or bend the connector, making it unusable.

Finally, do not assume the sensor is bad just because the appliance is not heating or cooling. Error codes can also mean a faulty control board, a broken heating element, or a failed compressor. If the new sensor does not fix the problem, have a technician check the other components before you spend more money on parts.

Frequently Asked Questions

How do I know if the sensor is actually broken?

If your oven or fridge displays an error code like "F1" or "E1" (codes vary by brand), the sensor is usually the culprit. You can also check by setting the oven to 350°F and waiting 10 minutes—if the temperature display does not change or stays at room temperature, the sensor is not working. For a fridge, if it is not cooling but the compressor is running, the sensor may be faulty.

Can I test the old sensor to confirm it is bad?

You can use a multimeter to test the sensor's resistance, but you need the correct resistance range for your model (usually between 1,000 and 10,000 ohms at room temperature). If you do not have a multimeter or are not comfortable using one, it is faster to straightforward install the new sensor and see if the problem goes away. The part is inexpensive enough that replacement is usually the practical choice.

What if the new sensor does not fit in the hole?

Check that you ordered the correct sensor for your exact model number. If the part number matches but the sensor still does not fit, the hole may be damaged or the sensor may be bent. Contact the parts supplier to confirm the part is correct, or return it for a refund. Do not force a sensor that does not fit, as you can damage the appliance wall.

Do I need to reset the appliance after replacing the sensor?

Most modern appliances do not require a reset. straightforward plug it back in and turn it on—the control board will recognize the new sensor automatically. If your appliance has a reset button or a power-reset procedure in the manual, you can follow that, but it is usually not necessary.

How long does a temperature sensor usually last?

Most sensors last 5 to 10 years, depending on how often you use the appliance and how well you maintain it. Ovens used daily may need a sensor replacement sooner than those used occasionally. Keeping the interior clean and dry helps extend sensor life, but eventually all sensors age and fail.