Location of the temperature sensor in the Bosch refrigerator: search and diagnostics

Finding the place where it is located temperature sensor in the Bosch refrigerator becomes critically important when the equipment ceases to correctly maintain the cold. Owners are often faced with a situation where food in the chamber freezes or, conversely, begins to spoil due to insufficient cooling. Understanding the design of the climate control system Bosch allows you not only to quickly find a fault, but also to avoid calling a technician for basic diagnostics.

Modern models of the German brand use a complex system of several sensors that transmit data in real time to the electronic control module. Thermal sensors can be located in completely different places: from the evaporator to the air ducts. Accurate knowledge of their location is necessary to carry out accurate resistance measurements with a multimeter. An error in determining the required sensor can lead to replacing a working part and the problem persisting.

This article will help you navigate the internal structure of your unit. We will analyze the types of sensors used in lines NoFrost and drip systems, and also consider typical symptoms of failure NTC resistors. Correct diagnostics will save you time and money, allowing you to make an informed decision about repairs.

Types of temperature sensors in Bosch refrigerators

In refrigeration equipment Bosch several types of temperature controllers are used, each of which performs its unique function. The main element is most often NTC thermistor, the resistance of which varies depending on the ambient temperature. Unlike old mechanical thermostats, electronic sensors are highly accurate, but are more sensitive to changes in voltage and humidity.

The control system can rely on the readings of one main sensor or use a network of several sensors for more accurate control. In models with a system NoFrost the number of sensors is always greater, since it is necessary to control the temperature not only in the chambers, but also in the evaporator area to prevent icing. Understanding the difference between these types is important when troubleshooting.

The most common configuration includes a refrigerator air sensor and an evaporator sensor. In two-compressor or dual-circuit systems, their number doubles. Some premium models are equipped with additional sensors in the zone zero zone or in the freezer compartment for the super-freezing function.

⚠️ Attention: Externally, all Bosch sensors look almost the same - it is a white plastic tip with two wires. Never rely on appearance alone, always check the resistance with a multimeter before replacing.

For electronics to function correctly, it is important that each sensor transmits the correct data. If thermistor gives false readings, the control module may erroneously start or, conversely, turn off the compressor. This leads to a violation of the temperature regime throughout the entire unit.

Symptoms of a thermal sensor malfunction

You can determine what temperature sensor has failed using a number of indirect signs that appear in the operation of the refrigerator. Most often, users notice that food in the refrigerator compartment begins to freeze, although the temperature regulator is set to medium values. This indicates that the sensor transmits underestimated readings to the control module, forcing the compressor to work without stopping.

The opposite situation is also possible: food quickly deteriorates, and the inside of the chamber becomes too warm. In this case, thermistor can show the module that the temperature has already reached normal, although in fact it is hot inside. In such cases, the compressor turns on rarely or operates in very short cycles, without having time to cool the volume.

Modern models Bosch are equipped with a self-diagnosis system that displays error codes on the display or signals by flashing indicators. Often a sensor malfunction is accompanied by codes related to the temperature of the evaporator or air in the chamber. Ignoring these signals can lead to more serious damage, for example, compressor failure due to overheating or water hammer.

You should also pay attention to the operation of the defrosting system. If “snow” or a coat of ice begins to accumulate in the freezer compartment or on the back wall of the refrigerator compartment, this may indicate a breakdown of the defrost sensor. It does not give a command to turn on the heating element, and the evaporator becomes overgrown with ice, blocking the air circulation channels.

• ❄️ Products in the refrigerator compartment freeze even at minimum power settings.
• 🌡️ The temperature inside the chambers differs significantly from the readings on the display or regulator.
• 🔊 The compressor operates continuously without stopping cycles or, conversely, too rarely.
• 💧 The appearance of ice, frost or ice plugs in the air ducts and on the evaporator.

Where is the sensor located in the refrigerator compartment

Searching for the main one air sensor in the refrigerator compartment of models Bosch usually does not take much time if you know where to look. In most cases, it is hidden inside a plastic casing or tunnel located on the back wall of the camera. This casing often covers the cold air supply channels and the evaporator itself.

To get to the sensor, you must carefully remove the shelves and drawers to gain free access to the rear panel. In some models, the sensor can be built directly into the control panel if it is located inside the camera, but in classic models Bosch it is placed on the rear wall. Fastening is usually carried out using plastic latches, which require careful handling.

The self thermistor is a small element that can be fixed in a special hole or simply hang on the wires inside the tunnel. It is important not to confuse it with the defrost sensor, which is located directly on the evaporator fins (behind the rear wall). The air sensor measures the temperature inside the chamber volume, so it should not be in direct contact with the ice evaporator.

When dismantling plastic panels, special care should be taken. Plastic becomes brittle in the cold, and one awkward movement can lead to breakage of the fasteners. Before starting work, it is recommended to let the refrigerator warm up a little or act as gently as possible, using plastic spatulas.

Location of sensors in the NoFrost system

B refrigerators Bosch with a system NoFrost the layout of the sensors is more complicated, since monitoring the evaporator defrosting process is critical here. The main defrost sensor (defroster) is always located in close proximity to the evaporator; it is often inserted into a special hole in the aluminum fins or attached to the freon pipe.

To access this unit in the freezer (or in a hidden compartment behind the rear wall of the refrigerator compartment, depending on the design), you will have to remove the fan and protective screens. The defrost sensor is responsible for turning on the heating element (heating element). If it is faulty, the system “thinks” that the evaporator has not yet warmed up and does not turn off the heating element, which is dangerous, or does not turn it on at all, which leads to ice fouling.

In addition, the system NoFrost may contain a “crying” evaporator sensor or a pan overflow sensor, although in models Bosch this is less common. The main attention should be paid to the pair: the evaporator sensor and the freezer air sensor. They are often located in the same wiring harness leading to the control module.

It is important to note that on some models the defrost sensor may be molded into the evaporator housing and cannot be replaced separately, requiring replacement of the entire assembly. However, in most cases Bosch uses standard replaceable elements that are easily diagnosed.

Table of typical resistances of Bosch sensors

For accurate diagnostics, it is not enough just to find the sensor, you need to measure its electrical parameters. NTC thermistors change their resistance depending on the temperature: the colder, the higher resistance, and vice versa. To check, use a multimeter in resistance measurement mode (Ohm).

Below is a table with approximate resistance values ​​for standard sensors used in technology Bosch. Remember that measurements should be taken at a known sensor temperature (for example, room or refrigerated).

If at room temperature the multimeter shows zero or infinity, the sensor is clearly faulty and requires replacement. If the readings are close to normal, but the refrigerator is not working correctly, it is worth checking the sensor in a cooled state by placing it in the freezer for 10-15 minutes.

Replacement process and important nuances

Replacement thermal sensor in the refrigerator Bosch is a procedure that can be done with your own hands, but requires care. Once you have reached the faulty element, you need to disconnect the connector. In some models, the connectors may be soldered to the module wiring, then soldering of the new sensor will be required, observing polarity (although polarity is not important for resistance, the tightness of the connection is important).

The new sensor must have identical characteristics. It is not recommended to install universal sensors without checking their resistance coefficient, since the control module will interpret the readings incorrectly. Original spare parts Bosch or high-quality analogues (for example, from Danfoss or Thermoworks) will ensure stable operation.

When installing a new sensor in the evaporator (for the NoFrost system), be sure to use thermal paste. It ensures tight thermal contact between the sensor and the metal of the evaporator. Without thermal paste, the sensor will respond to temperature changes with a delay, which will lead to ineffective operation of the defrosting system.

⚠️ Attention: When soldering the wires of a new sensor, use a soldering iron with a thin tip and do not overheat the connection so as not to damage the insulation of the wires, which may melt from high temperatures in the future.

After installation all elements back, reassemble the refrigerator in reverse order. Plug in the device and leave it to work without loading food for 2-3 hours. This will allow the system to return to normal and stabilize the temperature. Check the operation of the compressor and the absence of errors on the control panel.

Frequently asked questions (FAQ)