Modern brand refrigerators LG are complex electronic devices, where they are responsible for maintaining a stable microclimate a whole network of sensors. If you notice that your appliances have stopped freezing properly, or an error code appears on the display, the first thing you need to do is find the culprit - the sensor. Understanding their location and operating principle will help you quickly diagnose the problem without calling a technician.
The electronic control board receives real-time temperature data from these elements. Thermistor, as this component is correctly called, changes its resistance depending on the heat of the environment. When this process is disrupted, the compressor begins to work chaotically or does not turn on at all.
Refrigerators LG use a system No Frost or a combined cooling system, which implies the presence of several control points. Sensors can be located in the refrigerator compartment, freezer compartment, on the evaporator, or in the air ducts. Accurate knowledge of where is the temperature sensor in the LG refrigeratorwill save you time when disassembling.
The principle of operation and types of sensors in the No Frost system
The basis of the control system is NTC thermistor (Negative Temperature Coefficient). This means that as the temperature decreases, its electrical resistance increases, and as the temperature rises, it decreases. The control board reads these changes and makes a decision: turn on the compressor, start defrosting or activate the fan. If the sensor transmits incorrect data, the operating logic of the entire system is disrupted.
Depending on the refrigerator model LG, the number of sensors can vary from two to five. Basic models usually have one sensor in the refrigerator compartment and one in the freezer. More advanced versions are equipped with additional sensors for defrosting the evaporator and monitoring the temperature of the blown air.
It is important to understand that sensors in different zones can have different resistance at the same temperature. Replacing a sensor from the freezer with an analogue from the refrigerator will lead to incorrect operation of the unit. Therefore, when troubleshooting, always check the diagram of a specific model.
Some users confuse the temperature sensor with a thermostat. Older mechanical models used a thermostat that physically broke the circuit. In modern LG electronically controlled systems, everything is tied to a microprocessor that analyzes signals from thermistors.
Technical information
how does an NTC thermistor work?: The NTC thermistor is made of metal oxides. When heated, electrons gain energy and move more easily into the conduction band, reducing resistance. When cooled, the mobility of charge carriers decreases and the resistance increases. This is a non-linear process, therefore, for accurate diagnostics, tables of resistance and temperature correspondence are needed.
Location of sensors in the refrigerator compartment
The search for a sensor in the main compartment often begins from the back wall. In most models LG the air temperature sensor is built into a plastic casing that covers the air circulation system. It may be invisible, as it is disguised as a design element or ventilation grille.
To access it, you often need to remove shelves and drawers for vegetables. In some cases, the sensor is mounted on the evaporator body itself, which is hidden behind the rear panel. To get to it, you will have to dismantle the plastic cover by unscrewing the mounting screws or removing the latches.
Another common place is the area of the lampshade or next to it. Engineers LG often group climate controls at the top of the chamber. There may also be a sensor that controls the defrost temperature, if the refrigerator model requires it.
If you are looking for where is the temperature sensor in the LG refrigerator with a display on the door, pay attention to the wiring coming from the control panel. It often leads directly to the desired node. The sensor wires are usually thin, white or black, and end with a small plastic tip or metal sleeve.
Searching for sensors in the freezer compartment and on the evaporator
In the freezer compartment, the operating conditions are more severe, so the sensors here are more reliably protected. Most often they are mounted directly into evaporator or attached to its tubes with a special clamp. This allows you to control the temperature of the heat exchanger directly.
The defrost sensor is a critical element of the system No Frost. It tells the board when to heat the heating element to melt the ice, and when to turn off the heat so as not to damage the plastic and food. It is usually located in the lower part of the evaporator, where the main condensate accumulates.
In models with a bottom freezer, access to the sensor may be difficult. You will have to remove the top cover of the freezer or dismantle the entire evaporator unit. Be careful with the wires: in the cold, the insulation becomes rigid and can easily crack when bent.
Sometimes the sensor is hidden in a niche behind an ice container or behind a removable partition. Carefully inspect all accessible openings. If you see a wire going deep into the wall, most likely it leads to the thermistor.
☑️ Sensor search algorithm
Table of typical installation locations in different LG series
Model range of refrigerators LG is extensive, and the design may differ even within the same year of manufacture. However, there are general patterns that are characteristic of different series. Below is a summary of information that will help you navigate.
| Refrigerator series | Location of the refrigerator compartment sensor | Location of the freezer compartment sensor | Defrost sensor |
|---|---|---|---|
| LG GA (Top Freezer) | Inside the plastic casing on the rear wall | On the evaporator tube, access through the rear wall | At the bottom of the evaporator |
| LG GC (Bottom Freezer) | Behind the decorative duct panel | Mounted into the unit evaporator | Attached with a clamp to the evaporator |
| LG DoorCooling | In the upper part, next to the air supply area | Hidden in a niche behind the rear panel | In the drainage hole area |
| LG InstaView | Combined sensor block in the upper part | On the side wall of the evaporator | In the lower part of the heat exchanger |
This table is for reference only. The design of your specific model may have unique features. Always check the technical documentation or disassembly diagrams for your modification.
Fault diagnosis: multimeter and error codes
Before disassembling half of the refrigerator, it is worth carrying out an initial diagnosis. Modern refrigerators LG equipped with a self-diagnosis system that displays error codes on the display or indicates them by flashing lights. Codes starting with F or E (for example, rF, rS, E1, E2) often indicate problems with the sensors.
You will need a digital multimeter for an accurate check. It is necessary to switch the device to resistance measurement mode (Ohm). Disconnect the sensor connector from the control board or wiring harness. Measure the resistance at room temperature.
The normal resistance value at +25°C is usually about 5-10 kOhm (kilo-ohm), but the exact numbers depend on the model. If the multimeter shows an open (infinity) or short circuit (zero), the sensor is faulty. It is also worth checking the resistance in a frozen state - it should increase significantly.
A frequent problem is not the failure of the thermistor itself, but oxidation of the contacts in the connector or a broken wire at the entrance to the sensor housing. Carefully inspect the entire length of the wiring. Sometimes it is enough to clean the contacts for the refrigerator to work.
Replacing the thermistor: step-by-step instructions
If diagnostics confirm a malfunction, the component must be replaced. The replacement process requires care, as it involves working with plastic and electrical connections. First, make sure that you have a new sensor with the same characteristics.
Unplug the refrigerator. Remove all elements that interfere with access to the sensor (shelves, panels, covers). Disconnect the old sensor connector. If it is glued or pressed, carefully release it without damaging adjacent elements.
Install the new sensor in the same location. It is important to ensure close contact with the surface whose temperature it must measure. Use thermal paste if the sensor is inserted into a metal sleeve for better heat transfer.
Connect the connector, reassemble the refrigerator in the reverse order and turn it on. Check if the error code has disappeared. Let the equipment work for several hours to make sure that the temperature set is stable.
What will happen if you install a sensor with a different resistance?
If the resistance of the new sensor differs from the standard one, the control board will receive distorted temperature data. This will lead to the compressor turning on too often or rarely, food may freeze or spoil, and an ice coat will form on the evaporator.
Common mistakes during search and repair
One of the most common mistakes is ignoring safety rules. Working with live electrical appliances is prohibited. Always unplug the cord from the outlet before starting any manipulations inside the camera.
Another mistake is the use of physical force during disassembly. Plastic in refrigerators LG is secured with hidden latches. If the panel does not come off, it means that you forgot to unscrew a screw or did not release the latch. Excessive force will lead to breakage of the fasteners.
Also, users often forget to check the integrity of the wiring, focusing only on the sensor itself. A broken wire in a bundle that goes into the foam wall is a common fault that is easy to miss. Ring the entire circuit from the connector to the end of the wire.
⚠️ Attention: When dismantling plastic panels, proceed carefully. Plastic becomes brittle after prolonged cooling. A sudden movement can split the air duct housing or decorative trim, which will lead to air whistling and disruption of circulation.
⚠️ Attention: Technical characteristics of refrigerators may vary depending on the year of manufacture and region of sale. If you are not sure of your actions or (cannot find) the sensor according to the description, it is better to contact the official documentation or service center.
FAQ: Frequently asked questions
Is it possible to temporarily short-circuit the sensor to make the refrigerator work?
Theoretically, if you short-circuit the contacts (or install a resistor of the required value), the refrigerator can turn on. However, this will disable the temperature control system. The compressor will run continuously, which will cause food in the refrigerator compartment to freeze and ice to form. This solution is only for emergency diagnostics, but not for permanent operation.
How much does a temperature sensor for an LG refrigerator cost?
The cost of the thermistor itself is low, usually from 300 to 1000 rubles, depending on the model and seller. The main part of the costs when calling for service is the work of the technician and diagnostics. Self-replacement saves significant money.
Why does the new sensor not work?
There may be several reasons: incorrect installation (no contact with the surface), oxidized contacts in the connector, a wire break in the harness, or a malfunction of the control board itself, which cannot correctly read the readings of a working sensor.
Where to buy an original sensor?
Original spare parts can be ordered at authorized service centers LG or from official spare parts dealers. There are many analogues on the market that can work correctly if their resistance matches the original at different temperatures.