If your refrigerator Siemens starts to malfunction - the compressor does not turn off, the chambers do not maintain the desired temperature, or an error flashes on the display, the temperature sensor may be to blame. This small but critical element is responsible for the correct operation of thermoregulation. However, finding it is not so easy: depending on the model and cooling system (NoFrost, drip, combined), the location of the sensor varies.
In this article we will look at where exactly to look for the sensor in refrigerators Siemens of different series - from budget KG36N to premium iQ700. You will learn how to visually distinguish the sensor from other elements, what tools are needed for diagnostics, and what to do if it fails. And also typical mistakes when searching and checking, which even experienced craftsmen make.
How the temperature sensor in Siemens refrigerators works
The temperature sensor (thermistor) in refrigerators Siemens is thermistorthe resistance of which varies depending on the ambient temperature. The colder the chamber, the higher the resistance, and vice versa. This data is sent to the control board, which regulates the operation of the compressor and fans.
Most models Siemens use sensors NTC (with a negative temperature coefficient). Their key features:
- 🔹 Operating temperature range: from –40°C to +120°C (refrigerators usually use the range –30°C…+50°C).
- 🔹 Nominal resistance: at +25°C is 10–50 kOhm (depending on the sensor model).
- 🔹 Design: sealed housing made of plastic or metal with two terminals for connecting to wires.
- 🔹 Location: always in the area where you need to control the temperature (freezer, refrigerator compartment, evaporator).
In refrigerators Siemens with a system NoFrost there can be several sensors: separately for the freezer compartment, refrigerator compartment and even for the evaporator. Models with a drip system usually have one sensor, but it can be duplicated for measurement accuracy.
Where the temperature sensor is located: 3 main options
The location of the sensor depends on cooling systems i refrigerator designs. Below we will look at typical installation locations for different models Siemens, including photos and diagrams.
1. Refrigerators with the NoFrost system
In models Siemens with NoFrost (for example, series iQ500, iQ700, KG39), the freezer temperature sensor is usually located:
- 📍 On the evaporator (behind the back wall of the freezer compartment, under the plastic cover).
- 📍 In the air duct (if the model is with distributed cold MultiAirflow).
- 📍 On the ceiling of the freezer compartment (in some two-chamber models).
The refrigerator compartment sensor in NoFrost is most often located:
- 📍 Behind the plastic panel on the back wall (next to the fan).
- 📍 In the top corner of the chamber (under the lighting cover).
What does the sensor look like in NoFrost?
Usually it is a small cylinder with a diameter of 5–10 mm with two wires (black and white or red). Sometimes the sensor is enclosed in a plastic case with a latch for attaching to the wall. The photo below shows a typical sensor from the model Siemens KG39NXB30>:
2. drip system
In models with a “crying” evaporator (for example, KG36N, KG32), the refrigerator compartment temperature sensor is usually installed:
- 📍 On the back wall (directly on the evaporator or next to it, under the plastic panel).
- 📍 Inside the plastic box (if the evaporator is hidden).
For the freezer (if there is one), the sensor can be located:
- 📍 On the top shelf (attached to the wall or ceiling).
- 📍 Behind the ice boxes (in models with auto-defrost).
⚠️ Attention: In some budget models Siemens (for example, KG33N) the temperature sensor is combined with thermostat and is located inside the temperature control knob. In this case, replacement requires complete disassembly of the control panel.
3. Two-chamber and Side-by-Side models
In large ones. refrigerators Siemens (series iQ700, KS40, American Style) there can be up to 4-5 sensors:
| Sensor type | Location | Example models |
|---|---|---|
| Freezer compartment sensor | On the evaporator or in the air duct | Siemens KS40N, iQ700 |
| Refrigerator compartment sensor | Behind the back wall or under the light cover | Siemens KG39, KG49 |
| Environmental sensor | On the control board or next to the compressor | Siemens American Style |
| Evaporator sensor (for NoFrost) | Directly on the evaporator or in its housing | Siemens iQ500, KG36N |
How to find a temperature sensor: step-by-step instructions
To localize the sensor yourself, follow this algorithm:
Unplug the refrigerator|Remove all shelves and drawers from the chamber|Unscrew the back panel (if NoFrost) or plastic evaporator cover (drip system)|Look for a small cylinder with wires attached to the wall or tube|Check the resistance with a multimeter (should be ~10–50 kOhm at room temperature)-->
If the sensor is hidden behind the panel, proceed carefully:
- Turn off the refrigerator and wait for complete defrosting (if NoFrost, 1-2 hours is enough).
- Remove the plastic cover on the back wall of the chamber Siemens it. usually mounted with latches or screws
Torx T20. - Look for the sensor next to:
- 🔧 Evaporator (thin aluminum tube).
- 🔧 Fan (in NoFrost).
- 🔧 With a light bulb (sometimes the sensor is attached to its body).
In models with electronic control (For example, Siemens iQ500) the sensor can be integrated into the display board. In this case, its replacement requires complete disassembly of the control panel.
⚠️ Attention: In refrigerators Siemens with function Home Connect sensors may have non-standard connectors. Before replacing, take a photo of the connection or note the color of the wires!
Signs of a malfunctioning temperature sensor
If the sensor fails, the refrigerator Siemens begins to behave unpredictably. Here are the key symptoms:
- ❄️ The compressor works without stopping —the sensor “lies”, indicating a high temperature.
- 🔥 The chambers are too warm —the sensor does not transmit a signal to turn on the cooling.
- ⚡ Errors on the display (for example,
E1,E2,F04in models with Home Connect). - 💧 Frosting of the rear wall (in drip models) - the sensor does not regulate defrost correctly.
- 📉 Sudden temperature changes (products freeze or spoil).
To confirm the malfunction, check the sensor with a multimeter:
- Disconnect the sensor connector from boards.
- Switch the multimeter to resistance measurement mode (20 kOhm–200 kOhm).
- Measure the resistance of the sensor at room temperature (~20–25°C).
- Warm the sensor with your hand or a hair dryer - the resistance should be data-i="181">decrease diminish.
- Cool (for example, with ice) - the resistance should increase.
If the resistance does not change or is equal to 0/∞ - the sensor is faulty and requires replacement.
How to replace the temperature sensor in the refrigerator Siemens
Replacing the sensor is a task of average complexity. You will need:
- 🔧 Screwdriver
Torx T20or Phillips (depending on the model). - 🔧 Multimeter (to check the new sensor).
- 🔧 Soldering iron (if the sensor is soldered and not on the connector).
- 🔧 New sensor (select by refrigerator model or resistance).
Step-by-step instructions:
- Disconnect the refrigerator and defrost (if necessary).
- Remove the panel, behind which the sensor is hidden (see section above).
- Disconnect the connector or cut the wires (if the sensor is soldered).
- Install a new sensor, connecting it to the same wires.
- Check the resistance with a multimeter before assembly.
- Assemble the refrigerator and plug it into the network.
⚠️ Attention: In models Siemens with the system Home Connect after replacing the sensor, you may need to reset errors through the service menu. To do this, press and hold the buttonsSuper Cooling+Super Freezingfor 5 seconds.
Common mistakes when finding and replacing a sensor
Even experienced technicians sometimes make mistakes. cannot be done:
- 🚫 Confuse the temperature sensor with the defrost sensor (they are often installed side by side). NoFrost they are often installed side by side).
- 🚫 Use a sensor from another model - even if it is similar in appearance, the resistance may differ.
- 🚫 Forget to check the connectors —oxidized contacts can simulate a sensor malfunction.
- 🚫 Disassemble the refrigerator without disconnecting it from networks —risk of short circuit!
- 🚫 Ignore errors on the display —they tell you which sensor has failed.
Another common problem is incorrect installation of the new sensorFor example, if the model has Siemens KG39 sensor. put the refrigerator compartment too close to the light bulb, it will heat up and show incorrect data. The optimal distance from the heat source is at least 10 cm.
FAQ: Frequently asked questions about temperature sensors at Siemens
Is it possible to repair the temperature sensor or only replace?
The temperature sensor is non-repairable an element. If it fails, it can only be replaced. Attempts to repair (e.g., soldering contacts) usually lead to repeated failure within several months.
Which sensor to buy as a replacement for Siemens KG36N?
For the model KG36N a sensor with resistance 10 kOhm at 25°C is suitable (for example, original Siemens 00615750 or analogues Danfoss 067G2750, EPCOS B57863SCheck). the exact brand of the sensor according to the label on it or in the documentation of the refrigerator.
Why does the refrigerator not turn on after replacing the sensor?
Possible reasons:
- 🔌 Incorrect connection (wires are mixed up).
- 🔌 The control board does not recognize the new sensor (error reset needed).
- 🔌 Short circuit when soldering (check with a multimeter).
Is it possible to do without a temperature sensor?
Technically, the refrigerator will work, but the compressor will not turn offwhich will lead to:
- ❄️ Freezing cameras.
- ⚡ Overheating and compressor breakdown.
- 💰 Significant increase in electricity consumption.
Where can I find a sensor connection diagram for my Siemens model?
Connection diagrams are usually available:
- 📄 B service manual (search by model + "
service manual"). - 📄 On the sticker inside the refrigerator (sometimes part numbers are indicated there).
- 📄 On spare parts websites (for example, Siemens Parts, 4Service).