Owners of German brand equipment are often faced with the need to search for internal components when malfunctions occur. Temperature sensor is one of the key elements of the control system, and its incorrect operation can lead to food spoilage or the formation of excess ice. Understanding exactly where this element is located in your model Boschallows you to carry out initial diagnostics without calling a technician.
The location of the sensor directly depends on the type of cooling system: drip or NoFrost. In simple models, the element is often hidden behind plastic panels inside the refrigerator compartment, while in systems with full NoFrost there may be several of them, and they are scattered across different areas of the evaporator. Accurate knowledge of the design of your unit will help avoid damage to fragile plastic fasteners during disassembly.
In this article we will look in detail where to look for a temperature sensor in various series of refrigerators, what it looks like and what signs indicate its malfunction. The main sensor in Bosch models is most often hidden under a decorative cover on the back wall of the refrigerator compartment or built into the evaporator unit. We will also look at typical error codes that indicate problems with the temperature regime.
Types of sensors and their functions in the Bosch system
Before you start searching, you need to understand what is in modern refrigerators Bosch not one, but several sensors are used. The main one thermostat is responsible for turning the compressor on and off, maintaining the set temperature. Additional sensors can control the temperature of the evaporator to prevent it from freezing or monitor the climate in the freshness zone.
Electronically controlled models often use NTC thermistors, the resistance of which varies depending on the temperature. Their readings are read by an electronic module, which decides to start the cooling cycle. If sensor transmits incorrect data, the system may run idle or, conversely, freeze the entire contents.
There are the following types of sensors that may require your attention:
- 🌡️ Air sensor: measures the temperature directly in the chamber, usually located in a visible place or behind grille.
- ❄️ Evaporator sensor: fixed to the heat exchanger tubes, often hidden behind the rear panel.
- 🚪 Sensor defrost: monitors the defrosting process in the systems NoFrost.
⚠️ Attention: When diagnosing, remember that in different series of refrigerators (for example, KGN or KSV) the layout may differ. Do not use force when removing plastic plugs, as they may be brittle from the cold.
Location of the sensor in the refrigerator compartment
In most models of the refrigerator compartment Bosch with a drip defrosting system, the main air temperature sensor is located on the back wall. It is often covered with a plastic decorative cover, which can be round or oval. To get to it, sometimes it’s enough just to carefully pry off this pad, but in some cases partial disassembly of the internal space is required.
If you have a model with a zone VitaFresh, an additional sensor can be built directly into the container for vegetables or fruits. This allows you to maintain ideal storage conditions. In such cases thermal sensor looks like a small black rod protruding into the chamber, or is completely hidden inside the plastic body of the box.
To access the main sensor on the back wall, follow these steps:
- 🔧 Clear the chamber of food and remove shelves that block access to the rear wall.
- 👀 Find a round or oval plastic plug, often located at the center or just above the middle of the height.
- 🛠️ Carefully remove the plug using a flathead screwdriver to reveal the sensor itself and wires.
In some modifications, the sensor can be hidden behind a panel that covers the entire upper or lower sector of the rear wall. In this case, you will need to unscrew the mounting screws, which may be hidden under decorative plugs or stickers. Electronic module in such models, it receives a signal from this particular unit to regulate the operation of the compressor.
Searching for a sensor in the freezer and the NoFrost system
In freezers, especially in systems NoFrost, the situation is more complicated. Here defrost sensor and the evaporator temperature sensor are critical elements. They are located directly on the evaporator, which is hidden behind the rear panel of the freezer compartment. To access them, you will need to dismantle this panel, which is a more complex procedure.
Usually the sensors are mounted on the aluminum fins of the evaporator or inserted into special technological holes in the tubes. They are fixed with plastic clips or metal brackets. Visually, they are oblong elements of black or silver color, from which wires extend deep into the structure to the control unit.
Main locations in the freezer:
- ❄️ On the surface of the evaporator (behind the back wall).
- 🌬️ In the cold air supply channel (to control circulation).
- 🧊 In the defrost heater area (to control defrosting).
It is important to note that in two-compressor models Bosch each circuit has its own independent sensor system. An error in the freezer compartment does not always mean a problem with the main refrigerator compartment, and vice versa. However, if compressor works continuously, check the freezer sensors first.
Why do sensors in NoFrost fail more often?
In NoFrost systems, sensors are constantly subjected to cycles of freezing and defrosting, and also exposed to moisture. Over time, the seal of the housing is broken, condensation gets inside, which leads to oxidation of the contacts and a change in resistance.
Fault diagnostics and error codes
Modern refrigerators Bosch are equipped with a self-diagnosis system, which displays information about faults on the display or is signaled by flashing indicators. The most common codes associated with temperature sensors start with a letter E or F followed by numbers. For example, E1 or F1 often indicate problems with the refrigerator compartment sensor.
If you see a flashing temperature light or hear a beep, it may mean that thermal sensor is transmitting data out of range. The control module perceives this as a critical situation and goes into emergency mode. The table below shows common codes and their interpretation.
| Error code | Value | Probable cause |
|---|---|---|
E1 / F1 |
Faulty refrigeration sensor camera | Open circuit, short circuit, sensor failure |
E2 / F2 |
Faulty freezer sensor | Damaged wires, oxidation of contacts, module failure |
E3 / F3 |
Defrost sensor error | Problem with the evaporator sensor, heater sticking |
E6 |
Communication error with the module | Problems with the wiring between the sensor and the control board |
For accurate diagnosis, you need to “ring” the sensor with a multimeter. In normal condition at room temperature, its resistance should be a certain value (usually from 2 to 10 kOhm, depending on the model). If the device shows zero or infinity, element requires replacement.
☑️ Checking the sensor with a multimeter
Replacement process and technical nuances
Replacing the temperature sensor in the refrigerator Bosch is a procedure that requires accuracy. Once you have reached the faulty element, it must be disconnected from the electrical circuit. Often the wires are connected using special connectors that need to be carefully snapped off. In some cases, the wires may be twisted and insulated, then they will have to be disconnected and a new sensor connected through the terminal block.
The new one sensor is installed in the same mounting location. It is important to ensure tight contact with the surface it is to monitor (especially for evaporator sensors). If thermal conductive paste is used, apply a thin layer of it to the sensing element before installation. This will improve the accuracy of temperature reading.
⚠️ Attention: Never use regular electrical tape inside the chamber to insulate connections. In cold weather, the adhesive layer loses its properties and the insulation may be damaged, leading to a short circuit. Use only heat shrink or special terminals.
After installation, reassemble the structure in reverse order. Make sure all the latches are in place and the wires are not pinched by the plastic panels. The refrigerator should be turned on no earlier than 2-3 hours after completion of work, so that the refrigerant stabilizes.
Prevention and operating recommendations
To extend the life of temperature sensors and the entire control system, it is important to follow the operating rules. Sudden changes in voltage in the network can damage not only compressorbut also sensitive electronics, including sensors. It is recommended to use a voltage stabilizer or surge protector to protect the equipment Bosch.
Regular defrosting (for drip systems) and cleaning the drainage holes prevent the formation of ice plugs, which can mechanically damage the sensor or distort its readings. You should also avoid loading hot foods into the chamber, since a sudden temperature jump creates stress for the control system and can lead to a temporary failure of the sensors.
If you notice that the refrigerator began to work incorrectly immediately after a power surge, do not rush to disassemble it. Try performing a hard reset: disconnect the appliance from the network for 15-20 minutes. This will reset electronic module and may clear the software failure if the physical integrity of the sensors is not compromised.
Is it possible to temporarily short the sensor to make the refrigerator work?
Theoretically, shorting the wires could force the compressor work constantly, but it is extremely dangerous. The system will lose temperature control, resulting in food freezing, compressor failure due to continuous operation, and possible fire. This can only be done for a few minutes for diagnostics.
Where to buy an original sensor for Bosch?
Original spare parts are best ordered by catalog number (E-Nr) of your model in authorized service centers or specialized spare parts stores. The model number is indicated on the nameplate inside the refrigerator compartment.
Why does the error not disappear after replacing the sensor?
Some models require manual reset of the error through a combination of buttons on the control panel. It is also possible that the problem is not in the sensor itself, but in the wires going to it, or in a malfunction of the control board.