LG refrigerator thermostat: where it is, what it looks like and how to get to it

In this article you will find:

Below is a table with typical thermostat installation locations for different lines LG:

In models with mechanical control (temperature control knob), the thermostat is usually located directly behind this knob. In electronic refrigerators (LG InstaView Door-in-Door) it can be part of the general control unit, and its replacement will require special skills.

2. What does the thermostat look like in an LG refrigerator: photo and description

The appearance of the thermostat depends on its type:

• 🔘 Mechanical thermostat - it is a small box with a lever or handle, to which 2-4 wires and capillary tube (a thin metal tube going to the evaporator) are suitable. Example: thermostats K59-L1438 or WDF19.
• 📱 Electronic thermostat - often a microcircuit on a control board or a separate sensor with a connector. Found in models with a display (LG GC-B247SLBV).

The photo below shows a typical mechanical thermostat from a refrigerator LG GA-B399SLQZ:

Important! The capillary tube of the thermostat is filled with freon - it cannot be bent, pinched or damaged. comes off or is bent, the thermostat will have to be replaced.

3. thermostat

The process depends on the refrigerator model. Below are universal instructions for most LG with drip defrosting (series GA-B, GB-B):

1. Disconnect the refrigerator from the mains and remove all products from the refrigerator compartment.
2. Remove shelves and drawers that may interfere with access to the back wall.
3. Inspect the interior panel with the temperature control knob. It is usually secured with latches or screws (can be hidden under decorative plugs).
4. Carefully pry the panel out with a flat-head screwdriver or with a plastic spatula. In some models (LG GA-B409SLRZ), you will have to unscrew 2-3 screws.
5. Behind the panel you will see a thermostat - a plastic box with wires. Disconnect the connectors (remember their location!) and remove the thermostat along with the capillary tube.

For models c No Frost (LG GR-B379JVC) the process is more complicated:

• 🔧 You need to remove the inner rear panel of the refrigerator compartment (it is secured with screws).
• 🔌 The thermostat can be hidden behind the fan or next to the evaporator.
• ⚠️ Be careful - in systems No Frost there is a risk of damaging the defrost heater.

⚠️ Attention: In refrigerators LG with electronic control (series GB-B, GC-B with a display), the thermostat is often soldered into the board. Replacing it requires a soldering iron and skills in working with electronics. If you are not sure, it is better to contact the service.

4. Signs of a thermostat malfunction: how to distinguish it from other breakdowns

Symptoms of a faulty thermostat are often confused with breakdowns of the compressor, sensors or freon leak. Here exact signsthat the problem is in the thermostat:

• ❄️ The refrigerator does not turn on at all (the compressor is silent), but the light inside is on.
• 🔥 The compressor works without stopping, freezes too much or, conversely, does not cool.
• 🔄 The temperature in the chamber does not correspond to the one set on the handle (for example, +5°C is set, but in fact +15°C).
• 💡 When there are no clicks when turning the temperature adjustment knob (in mechanical thermostats).

Critical moment: if the refrigerator LG with electronic control shows an error Er FF or Er CF, the problem may not be in the thermostat, but in the temperature sensor or board. In this case, diagnostics with a multimeter is needed.

How to check the thermostat yourself:

1. Remove the thermostat (as described above) and disconnect the wires.
2. Switch the multimeter to resistance testing mode (ohmmeter).
3. Connect the probes to contacts 3 and 4 (usually they are responsible for closing/opening the compressor circuit).
4. Turn the thermostat knob: at minimum temperature the resistance should be 0 Ohm (closed), at maximum - ∞ (open).

⚠️ Attention: If the thermostat “sticks” in the closed state, the compressor will work without stopping, which will lead to overheating. If it is open, the refrigerator will not turn on at all. Both cases require replacement of the part.

5. Features of thermostats in LG refrigerators with No Frost and inverter compressors

In models with No Frost (LG GR-B379JVC, LG GC-B247SLBV), the thermostat often works in tandem with defrost sensor and an electronic unit. Here the thermostat can be:

• 📊 Digital —without a mechanical handle, controlled via a board.
• 🔌 Additional —for example, a separate thermostat for the freezer.

In refrigerators with inverter compressor (LG GB-B589SLQZ), the thermostat is integrated into the system Linear Cooling, where the temperature is regulated smoothly, without sudden on/off. Here, the thermostat is most often a thermistor (resistance sensor), rather than a mechanical relay. Replacing it requires calibration through the service menu.

Important for No Frost: if the refrigerator LG stops freezing, but the fan is working, the problem may not be in the thermostat, but in:

• 🔥 Defrost heater (check the resistance - it should be ~200–500 Ohms).
• ❄️ Frozen evaporator (you need to defrost the refrigerator for 24 hours).
• 📡 Temperature sensor (call with a multimeter).

6. How to replace the thermostat in an LG refrigerator: step by step

If the diagnostics confirmed that the thermostat is faulty, it needs to be replaced. To do this:

1. Buy analog of the original thermostat. For LG suitable parts marked:
   • K59-L1438 (for most models with drip defrosting),
   • WDF19 (for No Frost),
   • 240V 16A (universal mechanical thermostat).

Advice: After replacing the thermostat in electronically controlled refrigerators (LG GB-B***), you may need to reset the errors. To do this:

1. Disconnect the refrigerator from the power supply for 10 minutes.
2. Turn on and hold the "Super Cool" button for 5 seconds.
3. If the error persists, you need to flash the board.

⚠️ Attention: B models LG InstaView and Door-in-Door replacing the thermostat can lead to a failure of the electronic system. If after installing a new thermostat the refrigerator does not turn on, check the fuse on the board (usually a 250V SMD element).

7. when searching and replacing a thermostat

Even experienced users make mistakes that can aggravate the breakdown. Here are the most common ones:

• 🔌 Confused ones. wire - if you connect the thermostat contacts incorrectly, the compressor may burn out! Always mark the wires before disconnecting them!
• 🧊 Damage to the capillary tube —it cannot be bent or pinched. If the tube is torn, the thermostat will not work.
• 🔧 Using an incompatible thermostat —for example, setting the thermostat to 10A instead of 16A will lead to its rapid failure.
• 💡 Ignoring sensor checks — No Frost the problem may not be in the thermostat, but in the evaporator sensor (5301JA3008A).

Another typical error — incorrect diagnosis. For example, if the refrigerator does not freeze, but the light is on, it may not be the thermostat that is at fault, but:

• 🔋 Compressor start relay (check the winding resistance).
• ⚡ Thermal fuse (in models with No Frost it is located next to the defrost heater).
• ❄️ Leakage freon (detected by oil on the tubes or lack of pressure in the system).

FAQ: Frequently asked questions about the thermostat in the LG refrigerator