If your refrigerator LG suddenly stops freezing, and the compressor either does not start at all or makes short clicks and goes silent, in 80% of cases the culprit of the malfunction is the start relay. This small but critical element is responsible for applying voltage to the motor windings and then starting it. Understanding where exactly this unit is located in the design of your unit is the first and most important step to successfully restoring the functionality of the equipment.
In modern models of refrigerators LG, especially in lines with the system No Frost, the layout of the units may differ from the usual Soviet models. The relay does not hang outside on wires, but is often hidden inside a protective casing or integrated into the overall control system. The exact location of the relay depends on the specific series of the refrigerator and the type of compressor installed (conventional or inverter). Incorrect diagnosis or an attempt to disassemble the unit without knowledge of the circuit can lead to damage to other expensive parts.
In this article we will analyze in detail the architecture of the compressor compartment, consider the differences between classic and inverter models, and also provide a step-by-step algorithm for safe access to the starting mechanism. You will learn how to visually determine the malfunction and whether it is worth replacing the part yourself, or is it better to turn to professionals. Remember that any work with electrical components requires precautions.
The principle of operation and the role of the starting relay in the system
The starting relay in refrigeration equipment LG performs the function of an automatic switch. When the refrigerator is turned on, voltage is applied to the starting winding of the compressor motor, creating the necessary torque to start. As soon as the rotor reaches the required speed, the relay opens the starting winding circuit, and the engine continues to operate on the main winding. If this element fails, the compressor simply hums, but does not start, which can lead to overheating and combustion.
Classic models use an electromagnetic or thermal relay that physically opens the contacts. More modern units LG often use solid-state (PTC) relays that have no moving parts. They change their resistance when heated, which leads to an open circuit. Understanding the type of relay you have is important, since the methods for diagnosing and replacing them can vary significantly.
What is the danger of a faulty relay?
A faulty relay may not only not start the compressor, but also not turn off the starting winding. This leads to rapid overheating and burning of the motor windings, which will require replacing the entire compressor - the most expensive part of the refrigerator.
It is worth noting that in systems with inverter control there may not be a classic start relay as a separate hinged element. In such cases, the starting and monitoring functions are implemented within the electronic control module or the inverter unit itself. An attempt to find a “relay” in the usual sense on an inverter compressor may be unsuccessful, since it uses a fundamentally different engine operation scheme.
Relay location in classic LG refrigerator models
In most standard refrigerator models LG with a conventional piston compressor, the start relay is located directly on the side of the compressor housing. The compressor is usually located at the lower rear of the unit, in a special compartment covered with a metal or plastic cover. To get to the relay, you need to move the refrigerator away from the wall and remove this protective panel.
The assembly itself is a plastic box of black or white color, which is placed directly on three contact pins protruding from the compressor housing. Wires from the main electrical circuit of the refrigerator are connected to this box. In some older models, the relay may be additionally secured with a metal bracket or clip, which must be carefully pressed out.
- 🔍 Visual inspection: Look for a black plastic block, approximately the size of a matchbox, placed on the side of the motor.
- 🔌 Connection: Please note that the wiring harness always goes to the relay, coming from the general wiring of the refrigerator.
- ❄️ Environment: The relay is often located next to the capacitor (metal grill or coil at the back) and may be covered with a layer of dust.
When removing the casing, it is important to act carefully. Plastic becomes brittle over time, and contacts can oxidize. Before tightening the relay, it is recommended to photograph the wiring diagram so that when installing a new part you do not mix up the contacts. This will save time and protect you from errors during assembly.
Search features in LG inverter models
The situation with searching for relays in inverter refrigerators LG is radically different. These models use a frequency-converting compressor that does not require a classic start relay. Starting, stopping and adjusting the engine speed are controlled by sophisticated electronics - the inverter module. This module can be located either on the compressor itself or placed in a separate block at the bottom of the refrigerator.
If your refrigerator LG is equipped with an inverter compressor (usually this is indicated by the “Inverter” sticker on the front panel or in the documentation), then there is no point in looking for the usual PTC or electromagnetic type starting relay there. It's simply not there. Malfunctions in such systems are often associated with the inverter unit itself, sensors or control board, and not with the mechanical starter.
⚠️ Attention: An attempt to install a classic starting relay on an inverter compressor or connect it bypassing the standard electronics will lead to instant failure of expensive equipment. Inverter systems require professional diagnostics.
However, small relays may be present in some hybrid circuits or condenser fan control circuits. These are located on the main control board, which is often located at the top of the refrigerator compartment or in the service hatch at the rear. Access to them requires partial disassembly of the housing, which is not recommended to be done without the appropriate skills.
Step-by-step instructions for dismantling and access
In order to get to the relay and diagnose it, you need to perform a series of sequential actions. Failure to do so may result in damage to the refrigeration pipes or electrical parts. Before starting work, make sure that the refrigerator is unplugged for at least 30 minutes.
First remove the rear metal cover at the bottom of the unit. It is usually secured with several screws around the perimeter. After removing the cover, you will see the compressor (metal bulb) and condenser. Locate where the tubes and electrical wires exit the compressor housing. It is there, on the protruding contacts, that the required relay is located.
Disconnect the refrigerator from the power supply
Remove the rear protective cover
Take a photo of the wiring diagram
Prepare a flat-head screwdriver and multimeter
Ensure good lighting of the work area-->
Carefully disconnect the wires leading to the relay. If they are fixed with clamps, they need to be slightly pressed or the clamps pulled back. Then, holding the relay body, try to remove it from the compressor contacts. If it sits tightly, you can slightly rock it from side to side, but without excessive force, so as not to break the ceramic contact insulator on the compressor.
| Work stage | Action | Risks and nuances |
|---|---|---|
| 1. Preparation | Disconnecting from the network, moving the refrigerator | Risk of electric shock if the pause is not observed |
| 2. Access | Removing the rear cover of the compressor compartment | Do not damage the condenser tubes |
| 3. Removal | Disconnecting the wires, removing the relay from the contacts | Fragility of plastic, oxidation of contacts |
| 4. Diagnostics | Visual inspection and "testing" with a multimeter | The need to know resistance standards |
After removing the relay, inspect its insides. In the case of a PTC relay, there should be no cracks, burning or melting inside. If you hear that some object is dangling inside (except for the slight sound of a tongue in the electromagnetic relay), this is a sure sign of destruction of the internal structure of the part.
Diagnostics and signs of relay malfunction
You can determine that it is the relay that has failed by its characteristic signs. The most obvious symptom is that the compressor tries to start, there is a loud click, then a hum, and then a click again, after which the refrigerator goes silent. After some time, the cycle repeats. This indicates that the starting winding receives an impulse, but the engine does not start, and the thermal protection turns off the power.
Another sign is the characteristic smell of burning or melted plastic in the compressor area. If, during a visual inspection of the removed relay, you see blackened contacts or a melted body, replacement is necessary in any case. Even if the refrigerator starts working after cleaning the contacts, it will not last long.
- 🔊 Sound signals: Frequent clicks every few minutes without cooling.
- 🌡️ Temperature: The compressor may be hot, while the chambers are warm.
- ⚡ Electrical: Knocking out plugs or machines in the dashboard when trying to start.
For accurate diagnostics, use a multimeter. In a working PTC relay, the resistance should be within several tens of ohms (usually from 5 to 50 ohms, depending on the model). If the device shows infinity (open) or zero (short circuit), the part is faulty. Also check the thermal relay (if it is separate) - its contacts should “ring” short in a cold state.
Replacing the relay and precautions
Replacing the relay in the refrigerator LG is a technically simple procedure, but requires care. The main rule: the new part must completely match the old one in terms of markings and parameters. There are no universal relays; each type of compressor requires its own starting device. The marking is usually applied to the side or top edge of the plastic case.
Installation is carried out in the reverse order of removal. Push the new relay onto the compressor contacts as far as it will go, making sure it fits tightly and does not wobble. Then connect the wires according to the photographs or color coding you took earlier. Usually the circuit is simple, but an error in the connection may result in a short circuit.
⚠️ Attention: Make sure that the orientation of the relay (vertical or horizontal) is the same as the original. Some relays only operate in a certain position due to the design of the internal spring or opening mechanism.
After assembly, do not rush to close the back cover. Plug in the refrigerator and listen. Startup should be quiet, without loud clicks or buzzing. The compressor should pick up speed and operate evenly. If everything went well, you can screw the lid and move the refrigerator to the wall.
Is it possible to use a relay from another brand?
Theoretically, if the mounting dimensions, voltage and current are the same, a relay from another brand (for example, Danfoss or Secop) may be suitable. However, to guarantee reliability, it is better to look for an original LG article or a complete analogue in the catalog.
Frequently asked questions (FAQ)
Is it possible to repair a burnt-out relay yourself, for example, by cleaning the contacts?
In the case of modern PTC (solid-state) relays, repair is impossible, since there is a ceramic element inside, which when overheated is destroyed irrevocably. Electromagnetic relays can theoretically be disassembled and the contacts cleaned, but this is a temporary measure. Considering the low cost of a new part, replacement is the only reasonable solution.
How much does it cost to replace a relay in a service center compared to self-repair?
The cost of the part itself ranges from 500 to 1500 rubles, depending on the model. At the service center, the cost of the technician’s visit and work will be added to the price of the part, which in total can range from 2,500 to 4,000 rubles. Self-replacement saves money, but requires minimal skills in working with the tool.
Why does a new relay burn out a short time after replacement?
This may indicate a more serious problem, for example, an interturn short circuit in the compressor windings or a malfunction of the thermostat. If the compressor is “heavy” or seized, it consumes a starting current higher than the nominal value, which leads to rapid failure of even a new relay. In such cases, diagnostics of the motor itself is required.
Where to buy an original relay for an LG refrigerator?
Original spare parts can be purchased at authorized LG service centers, specialized stores of spare parts for household appliances, or on large online platforms. When purchasing, be sure to check the article number (part number) with the old part. Analogs from third-party manufacturers (for example, MRC, Indesit) may also be suitable if the electrical parameters match.