Location and replacement of the thermostat in LG refrigerators

Finding the place where the thermostat is located on an LG refrigerator often becomes a priority when the equipment no longer supports correctly temperature regime. Modern units of this brand can be equipped with both classic mechanical regulators and complex electronic control systems, which significantly affects the search algorithm. Understanding the design of your device is the key to successful repair or diagnosis without calling a technician.

In most older models and some budget series LG the thermostat is a physical switch associated with a sensing element. In newer No Frost systems, temperature control is carried out electronically, where thermistors or temperature sensors act as a mechanical circuit breaker. That is why the first step should always be to identify the type of control of your refrigerator.

If you are faced with a situation where the compressor runs without stopping or, conversely, does not turn on at all, the problem often lies precisely in the temperature control circuit. Thermoregulator (or thermostat) is responsible for opening and closing the electrical circuit depending on the temperature in the chamber. Incorrect diagnosis can lead to the purchase of unnecessary spare parts, so it is important to accurately determine the type of unit.

Determining the type of temperature control system

Before disassembling the unit, you need to clearly understand what modification you are dealing with. LG refrigerators released more than 10-15 years ago commonly used mechanical thermostats. They are easily recognized by the characteristic rotary handle inside the refrigerator compartment, on which the numbers from 1 to 7 or Min/Max designations are printed. The rotation of this knob mechanically affects the contacts inside the thermostat housing.

Modern models, especially those equipped with a system No Frost and a display on the door, are controlled electronically. In such devices there may not be a physical “thermostat” in the classical sense (as a separate replaceable part with a bellows). Its function is performed temperature sensors (thermistors), which transmit signals to the main control unit. Replacing a mechanical thermostat in an electronic refrigerator is impossible, since it uses a fundamentally different circuit.

⚠️ Attention: An attempt to install a mechanical thermostat instead of an electronic sensor in modern LG models will lead to incorrect operation of the compressor and possible failure of the control board.

To accurately determine the type of system, look at the technical data sheet of the device or find a sticker with the model inside the camera. If the model name contains letters indicating the presence of an inverter compressor and an electronic display, most likely you are not looking for a thermostat, but a touch sensor. However, if you have a classic model with a drip defrosting system and a twister inside, then the search for a mechanical unit is completely justified.

Location of the thermostat in mechanical models

In classic LG refrigerators, the mechanical thermostat is most often hidden from the user's eyes. Although the control knob is located inside the refrigerator compartment, the actuator itself is located outside, at the top of the unit. To get to it, you usually need to remove the top cover of the refrigerator or the plastic casing covering the top of the chamber.

The design of the unit is a metal or plastic box with three or four contacts, to which a long capillary tube fits. This tube is inserted into the chamber and attached to an evaporator or a special clip. It is the length and position of this tube that determines where the main regulator unit is physically located - usually in the technical compartment above the refrigerator compartment or behind the top panel.

• 🔍 Upper technical compartment: the most common location accessible after removing the cover.
• 🔍 Behind the lampshade: in some models the thermostat housing is integrated into the unit lamps.
• 🔍 Inside the chamber (rarely): in very old models, the housing may be partially visible behind the plastic handle cover.

It is important to note that the capillary tube is very fragile. If handled carelessly, it may burst, which will lead to freon leakage from the thermoregulation system and complete inoperability of the part. Capillary Do not bend at an acute angle or stretch with force. If you are planning a replacement, proceed with extreme caution so as not to damage the sensitive element.

Removal and access to the thermostat

The process of gaining access to the thermostat requires compliance with safety precautions. The first step should always be to completely unplug the refrigerator. Even if you are only replacing the mechanical part, the risk of a short circuit or electric shock if you accidentally touch live contacts is too great. After turning off, let the unit stand for 10-15 minutes.

To remove the top cover you will need a Phillips screwdriver. On some LG models, the screws may be hidden by decorative plugs or located under the door hinges. If the hinges interfere with removing the cover, it is better to remove the door, first fixing its position so as not to damage the wiring or the door itself. Carefully unscrew all visible fasteners.

After removing the cover you will see insulation (polyurethane foam or glass wool). The thermostat is usually mounted on a metal bracket or plastic holder next to the evaporator. Disconnect the wires after photographing their location, since it is very easy to mix up the contacts 3-4 or 3-6 and this will lead to improper operation of the compressor.

Diagnostics and performance testing

Before buying a new part, you should make sure that the problem is in thermostat. There can be several symptoms of a malfunction: the refrigerator does not freeze, it freezes too much (turning food into ice), or the compressor hums but does not start. However, similar signs may indicate problems with the start relay or the compressor itself.

The most reliable way to check is to test the contacts with a multimeter in resistance measurement mode. To do this, you need to remove the thermostat, disconnect the capillary tube (if the design allows) or simply cool the body of the part. When warm, the mechanical thermostat contacts are usually closed. If you place the sensitive tube in the cold (for example, in a freezer for 15 minutes), the contacts should open and the resistance will become infinite.

If the multimeter shows zero at any temperature, it means that the contacts are “stuck” and the compressor will work continuously without turning off. If the resistance is infinitely large even in warm conditions, the circuit is broken and the refrigerator will not turn on. In both cases, you need to replace the part with an analogue with markings corresponding to your model. LG.

Replacing the thermostat: step-by-step instructions

Replacing the thermostat on an LG refrigerator is a procedure accessible to a person with basic skills in working with tools. The main requirement is to buy exactly the same part. The marking is usually applied to the metal case (for example TAM-133, K-59 etc.). Different models have different capillary tube lengths and response temperatures, so there are no universal solutions here.

Install the new thermostat into the seat, secure it with standard screws or clips. Pay special attention to the laying of the capillary tube: it should lie in the same groove or clip as the old one and fit snugly to the evaporator. If the tube hangs in the air, the thermostat will “lie”, reacting to the air temperature in the chamber, and not to the temperature of the evaporator.

⚠️ Attention: The length of the capillary tube of the new thermostat may differ from the old one. The excess cannot be cut off or twisted into tight rings - this will disrupt the operation of the bellows. Carefully place the excess length with a snake in the free space of the technical compartment.

Connect the wires according to the photographs taken earlier. Mechanical thermostats typically have three main contacts: one for the phase input, one for the compressor, and one for the lamp (or second output). After assembling all the panels and returning the refrigerator to its original position, turn it on. For the first few hours of operation, follow the cycle: the compressor should turn on and off at certain intervals.

Electronic temperature sensors in refrigerators LG

In models with electronic control (Linear Cooling, Door Cooling+), you will not find the usual “twist” and mechanical unit. Here, thermistors are responsible for the temperature - small parts whose resistance changes depending on the heating. They can be located at different points: in the air duct, on the back wall of the refrigerator compartment, in the freezer evaporator area, or even in the door body itself.

Diagnostics of such sensors is only possible using a multimeter and a resistance table for a specific LG model. Typically at room temperature the resistance is about 5-10 kOhm, and when cooled it increases. If the sensor is “lying,” error codes may appear on the display (for example, rF, Er FF), indicating a problem with defrosting or temperature.

Replacing the electronic sensor is more difficult, since it often requires partial disassembly of the internal plastic of the camera. Unlike mechanics, not only the part itself is important here, but also the integrity of the cable going to the control board. A broken wire in the harness is a common cause of failures, which can easily be confused with a malfunction of the sensor itself.