Failures in the cooling system often become an unpleasant surprise for the owner of household appliances. If the refrigerator stops turning off, runs continuously, or, conversely, stops freezing, the cause may be a failure. thermal sensor. This small element is responsible for reading the temperature inside the chambers and transmitting a signal to the electronic control module.
Before embarking on complex repairs, it is necessary to carry out initial diagnostics. Replacing the sensor is a procedure that you can do yourself if you have a basic set of tools and an understanding of the unit's structure. However,
In this article we will analyze in detail the algorithm of actions that will help you remove the temperature sensor without damaging the plastic elements of the case and wiring. We will look at the features of dismantling for various types of sensors used in modern models Indesit, LG, Bosch and other popular brands.
⚠️ Attention: Before starting any work on disassembling the refrigerator, be sure to disconnect the device from the electrical network. Working with electrical appliances under voltage is life-threatening.
Operating principle and types of thermal sensors
A thermal sensor, or thermistor, is a semiconductor device whose resistance varies depending on the ambient temperature. The electronic control unit reads these changes and decides whether to turn the compressor on or off. Modern models use several of these elements to monitor different zones.
There are two main types of sensors that may require replacement. The first type is the classic thermostats mechanical action, which is more often found in older models. The second type is electronic NTC thermistors, installed in refrigerators with a system No Frost and electronic control. It is these that we will consider in the context of removal and replacement.
The location of the elements depends on the design of the unit. They are usually located in the evaporator, in the air ducts or directly in the plastic housing of the chamber. Understanding which sensor has failed is critical for correct diagnosis.
How to determine a malfunction without instruments?
If the refrigerator runs non-stop and the temperature inside drops below normal, or the compressor does not turn on at all, although the light is on, the sensor is likely to fail. An error may also be indicated by blinking indicators on the control panel.
Required tools for dismantling
To properly perform the job of replacing the temperature sensor, you will need a minimum set of tools. The main requirement is accuracy, since the plastic in refrigerators is often fragile, especially if the device is several years old.
You will need the following tools:
- 🔧 Screwdrivers (Phillips and flathead) for removing panels and fasteners.
- 🔪 Plastic spatula or an old bank card for neat opening the latches.
- ✂️ Pliers or tweezers for removing small parts and working with wiring.
- 🔦 Flashlight for illuminating hard-to-reach places inside the cameras.
It is also recommended to prepare a multimeter if you plan not only to remove, but also to check the serviceability thermistor. Without checking the resistance, it is impossible to say for sure whether replacement is needed, although visual damage to the insulation is also a reason for replacement.
☑️ Checking readiness for repair
Access to the sensor in the refrigerator compartment
If the problem concerns the main chamber, then most often the sensor is hidden behind a plastic panel on the back wall or side. In some models Samsung i LG it can be integrated into the lampshade or door handle.
The removal process begins with freeing up space. Remove all shelves and products so that nothing obstructs your view. Locate the plastic cover covering the back of the camera. It can be attached with screws or held on by latches.
Carefully unscrew the visible screws. If there are no screws, use a plastic spatula to unclip the fasteners around the perimeter of the panel. Operate without sudden jerks so as not to break plastic clips. After removing the panel, you will see the evaporator and the tubes suitable for it.
The sensor itself is usually fixed in a special hole or attached to the evaporator with a clamp. The wiring from it goes to the electronic module. To remove the element, you need to disconnect the connector, which is often located outside the camera, in the technical compartment, or directly under the panel.
Removing the sensor in the freezer compartment and the No Frost system
In the freezer compartment, especially in the systems No Frost, access to the sensor is complicated by the presence of ice and a more complex design of the air ducts. Here, thermal sensors are responsible for defrosting the evaporator and controlling the freezing temperature.
For access, it is often necessary to remove the back panel inside the freezer. If the unit has not been completely defrosted, frozen ice may prevent the panel from being removed. In this case, do not use force - use a hairdryer (at minimum power and with caution) or wait for complete natural defrosting.
After removing the panel, you will find the evaporator. The defrost sensor is usually mounted on the evaporator fins or inserted into a special socket. Its wiring passes through the hole in the housing to the control unit.
When removing, be careful about the condition of the wires. Low temperatures make insulation hard and brittle. A sudden movement can lead to a wire break, which will require a more complex restoration of the wiring, rather than just replacing the sensor.
⚠️ Attention: Do not use sharp metal objects (knives, screwdrivers) to chip ice around the sensor. You can damage the aluminum tubes of the evaporator or the sensitive element itself.
Technical characteristics and testing with a multimeter
Before installing a new sensor, you need to make sure that the old one is working or check that the parameters of the new one are in compliance. Thermal sensors have different resistances at room temperature (usually 25°C). The most common values are 5 kOhm, 10 kOhm, 15 kOhm and 50 kOhm.
To check, use a multimeter set to resistance measurement mode. Connect the probes to the sensor contacts. At room temperature, the device should show a value close to the nominal value specified in the documentation.
A more accurate test method is the “ice test”. Place the probe tip in a container of water and ice (temperature around 0°C). The resistance must change. If the readings do not change or go to infinity (break), the part is faulty.
Below is a table with approximate resistance values for popular types of sensors at different temperatures:
| Sensor type | Resistance at 25°C | Resistance at 0°C | Application |
|---|---|---|---|
| NTC 5k | 5.0 kOhm | 15.0 kOhm | Refrigerator compartment |
| NTC 10k | 10.0 kOhm | 30.0 kOhm | Freezer compartment |
| NTC 15k | 15.0 kOhm | 45.0 kOhm | No Frost system |
| NTC 50k | 50.0 kOhm | 120.0 kOhm | Evaporator |
If you are not sure about the type of sensor, it is best to remove the old one and look for an analogue by catalog number or appearance. Installing a sensor with an inappropriate rating will lead to incorrect operation of the refrigerator.
Installing a new temperature sensor and assembling
The process of installing a new element is performed in reverse order. Insert the sensitive tip of the new sensor into the seat until it stops. Make sure that it fits tightly to the surface from which you want to read the temperature.
Secure the sensor with standard fasteners. If the factory fastening is broken, you can use heat-resistant glue or aluminum tape, but try to maintain the original fixing method. Place the wiring in standard channels, avoiding kinks and contact with sharp metal edges.
Connect the wiring connector. It should click into place with a characteristic click. After this, reinstall the plastic panels, securing all screws and latches. Return the shelves and food to the chamber.
Plug in the refrigerator. For the first few hours, the device will work in enhanced mode, gaining temperature. Do not open the doors during this period. If after 5-6 hours the refrigerator got cold and turned off (or switched to temperature maintenance mode), it means the replacement was successful.
Frequent errors during replacement and precautions
When making repairs on their own, beginners often make mistakes that ruin all their efforts. One of the most common is damage to the wiring when dismantling the panels. Always check the integrity of the wires before throwing away the old sensor.
Another mistake is using the wrong insulation. Regular electrical tape may not withstand low temperatures and may peel off, resulting in a short circuit. Use only heat shrink or specialized materials.
It is also important not to confuse the sensors if there are several of them in the refrigerator. The refrigerator compartment sensor and the evaporator sensor have different characteristics. Installing them will result in the refrigerator not working properly, possibly with constant freezing.
⚠️ Attention: Technical specifications and location of components may vary depending on the specific model and year of manufacture. Always check the official schematic diagram for your device, if available.
If after replacement the refrigerator continues to operate incorrectly, the problem may not lie in the sensor, but in the control module or compressor. In this case, it is better to contact a professional technician for in-depth diagnostics.
Questions and answers (FAQ)
Is it possible to temporarily short-circuit the sensor to make the refrigerator work?
Shorting or installing a resistor with a fixed resistance is only possible as a temporary measure for diagnostics. In this case, the refrigerator will either work constantly or will not turn on at all, since the module will not receive real temperature data. Operation in this mode is dangerous for the compressor.
Where to buy a suitable temperature sensor?
Original spare parts are best ordered from authorized service centers or specialized spare parts stores for household appliances. When purchasing, be sure to name the model of the refrigerator or show the markings of the old sensor.
How long does it take to replace the sensor?
For an experienced technician, the process takes 20-40 minutes. For a beginner who is disassembling the refrigerator for the first time, this can take from 1 to 2 hours, including time for carefully removing the panels and defrosting the ice.
Why did the new sensor immediately burn out?
This can happen due to a power surge in the network, a malfunction of the control module (which supplies the wrong voltage) or moisture getting on the contacts immediately after switching on. It is also possible to install a part with an incorrect power rating.