Relay in a Bosch refrigerator: where is it located, how to check and replace

When a refrigerator Bosch suddenly stops freezing, makes strange clicks or does not turn on at all, the first suspicion falls on the start-up relay. This small but critical element is responsible for starting the compressor and protecting against overloads. However, finding it in modern models is not always easy: the manufacturer often hides the relay under decorative panels or integrates it into electronic modules. In this article we will look at where exactly to look for relays in refrigerators of different series (from classic to inverter Bosch not always simple: the manufacturer often hides the relay under decorative panels or integrates it into electronic modules.

In this article we will look at where exactly to look for relays in refrigerators Bosch different series (from classic KGE36... to inverter KIN86...), how to visually distinguish it from other parts, and what to do if the relay fails. You will also find out what tools are needed for diagnostics and whether it is possible to do without calling a technician.

Why do you need a relay in the refrigerator and how does it work

The start-up protection relay is an “intermediary” between the electrical network and the compressor. Its main functions:

• 🔌 Start the compressor: when power is applied, the relay closes the circuit, allowing current to pass to the motor windings.
• ⚡ Overheat protection: if the compressor runs too long or is overloaded, the relay opens the circuit, preventing breakdown.
• 🔄 Control of starting currents: at the moment of start, the current can exceed the rated current by 5–7 times - the relay smoothes out this jump.

In refrigerators Bosch two types are used relays:

1. Electromechanical (classic, with a coil and contacts) - installed on models before 2015 (for example, KGN39...).
2. Electronic (solid-state, in a plastic case) - typical for modern lines KIN..., KAN... with inverter compressors.

Signs of a relay malfunction:

• 🔊 The compressor does not start, but you can hear clicking (the relay is trying to work).
• ❄️ The refrigerator does not cool, although the light inside is on.
• ⚡ The device knocks out the machine in the panel when turned on.
• 🔥 The relay body is hot to the touch (indicates a short circuit).

Where is the relay located in Bosch refrigerators: search by model

The location of the relay depends on refrigerator series and the type of compressor. Below are typical layouts for popular lines of Bosch.

1. Classic models with drip defrosting (KGN36..., KGE39..., KIV38...)

In refrigerators older than 2015, the relay is usually attached directly to the compressor housing (black metal cylinder at the bottom of the rear wall). You need to look for it:

• 📍 To the right or left of the compressor, screwed with two screws.
• 🔌 Connected to the compressor with three wires: two thick (power) and one thin (control).

Visually, the relay looks like a small box (the size of a pack of cigarettes) with a plastic cover. There may be a sticker on the lid with marking RBM-45, DANFOSS 103N0022 or similar.

2. Modern models with NoFrost (KIN86..., KAN58..., KAD90...)

In refrigerators with the system NoFrost (2016–2026) the relay is often integrated into the electronic module or hidden under the decorative panel. Where to look:

• 📍 Inside a plastic box next to the compressor (often covered with a foam cover).
• 🔧 Under the back panel of the refrigerator, closer to the lower left corner.
• 🖥️ In some models (for example, KIN86VF30R) relay soldered into control board —its replacement requires soldering.

Electronic relays in these refrigerators look like a small plastic box with 3-4 legs for mounting on the radiator. Markings may include codes RLS-8, Bosch 00642379 or EVRDF102H01X.

3. Inverter refrigerators (KIU81..., KIV87...)

In models with inverter compressors (Inverter Compressor) a traditional start-up relay absent. Its functions are performed by electronic control unit, located:

• 📍 On the back wall, in the upper part (under the cover next to the display).
• 🔌 Connected to the compressor with a multi-core cable (4-6 wires).

If such a refrigerator does not turn on, the problem may lie in the control unit itself or in the temperature sensors. Diagnostics requires special equipment (for example, a tester Bosch BSH Diagnostic Tool).

How to distinguish an inverter compressor?

Inverter models Bosch have the inscription "Inverter Compressor" or "Digital Inverter" on the sticker on the back. They also operate almost silently (without the characteristic "growling" when starting).

⚠️ Attention: In refrigerators Bosch with a system VitaFresh (for example, KGN39VL30R), the relay may be hidden under the vegetable tray. Before searching, be sure to unplug the appliance and remove all shelves!

How to check a Bosch refrigerator relay with a multimeter

If you find the relay, but are not sure of its functionality, you can carry out diagnostics using a multimeter. You will need:

• 🔧 Multimeter (resistance and circuit test mode).
• 🔌 Screwdriver (for removing the relay).
• 📸 Camera (to capture the wiring diagram).

Procedure:

1. Unplug the refrigerator and turn it with the back wall towards you.
2. Remove the relay from the compressor (unscrew the screws or unclip the clamps).
3. Disconnect the wires, having previously photographed their location.
4. Ring the relay contacts:
   • 🔹 Between the terminals S (start) and M (motor): resistance should be 0–50 Ohm.
   • 🔹 Between S and L (line): in normal condition - infinity (open).

If at room temperature the contacts S-L are closed, the relay is faulty.

For electronic relays (plastic case), the test is more complicated: you will need to measure the output voltage when power is applied. If at the output terminals. no 220–240 V when the refrigerator is turned on, the relay must be replaced.

Disconnect the refrigerator from the network|Take a photo of the wire connection|Ring the S-M contacts (resistance 0–50 Ohm)|Ring the S-L contacts (should be open)|Check the integrity of the relay case-->

⚠️ Attention: Do not touch the relay contacts with bare hands during the test - the residual charge in the capacitor can cause electric shock!

Replacing the relay in a Bosch refrigerator: step-by-step instructions

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

1. Choose an analogue:
   • 🔍 For electromechanical relays, universal models are suitable RBM-45, DANFOSS 103N0022 or Bosch 0000133604.
   • 🔍 For electronic ones - only original ones (for example, Bosch 00642379 for series KIN...).

   The marking of the old relay can be found on its body or in the instructions for the refrigerator.

2. Remove the old relay:
   • 🔧 Unscrew the mounting screws (usually two, for a Phillips screwdriver).
   • 🔌 Carefully remove the terminals, do not pull the wires!
3. Install a new relay:
   • 📸 Check the photo of the wire connection.
   • 🔧 Attach the relay to the compressor (the screws should be tightened tightly, but without force).

Check the operation:

• 🔌 Plug in the refrigerator.
• 👂 Listen: you should hear the relay click and start compressor.

If after replacing the relay the refrigerator does not work:

• 🔹 Check thermostat (it may not give a start signal).
• 🔹 Inspect compressor for mechanical damage.
• 🔹 Make sure that mains voltage stable (220–240 V).

Common mistakes when replacing a relay and how to avoid them

Even experienced craftsmen sometimes make mistakes that lead to repeated breakdowns. Here's what cannot be done (for example, from:

• ❌ Use a relay from a different brand (for example, from Indesit or SamsungEven if it looks similar, the response parameters can). differ.
• ❌ Connect the wires at random. The reversed phase and zero will lead to a short circuit.
• ❌ Fasten the relay loosely. Vibration of the compressor can break the contact.
• ❌ Ignore checking the compressor. If the compressor is jammed, the new relay will burn out immediately after installation.

Critical error: trying to repair the electronic relay by soldering without special skills In 90% of cases, this leads to. damage to the board tracks and the need to completely replace the control module.

If, after replacing the relay, the refrigerator turns on, but turns off after a few minutes, the reasons may be the following:

• 🔹 The thermostat is faulty (measures the temperature incorrectly).
• 🔹 The capillary tube is clogged (compressor overheats).
• 🔹 Weak voltage in the network (the relay operates as protection).

⚠️ Attention: In refrigerators Bosch with display (series KIN..., KAD...) after replacing the relay, you may need to reset errors through the service menu. To do this, press and hold the buttons Super + Eco for 5 seconds.

When it is better to call a repairman: complex cases

Not all breakdowns the relay can be repaired yourself. Contact a specialist if:

• 🔧 The relay is soldered into control board (soldering of SMD components is required).
• 🔌 Refrigerator knocks out the machine in the panel when turned on.
• 🖥️ The display shows an error E22, E24 or F04 (relay or compressor fault codes).
• ⚡ After replacing the relay, the compressor buzzes, but does not start (possibly an interturn short circuit in the windings).

Cost of replacing the relay in the service center Bosch (at 2026):

• 💰 Replacement of the electromechanical relay: 1 500–2 500 ₽ (taking into account the work).
• 💰 Replacement of the electronic relay or control unit: 3 000–6 000 ₽.
• 💰 Diagnostics (if the cause is not relay): 1 000–1 500 ₽.

If your refrigerator is under warranty, do not disassemble it yourself this will void the warranty. Official service centers Bosch in Russia can be found on the manufacturer's website at link.

FAQ: Frequently asked questions about relays in Bosch refrigerators

Is it possible to replace an electromechanical relay with an electronic one?

No, these types of relays are not interchangeable. Electronic relays are designed to work with inverter compressors and have a different control algorithm. Installing an electronic relay instead of an electromechanical one will lead to incorrect operation of the refrigerator or breakdown. compressor.

How to check the relay without a multimeter?

If you don’t have a multimeter, you can use the “replacement method”: temporarily install a known working relay (for example, from another refrigerator of the same model). If the refrigerator works, the problem is in the relay. Also pay attention to external signs:

• 🔥 Darkening or melting of the case.
• 💨 Burning smell when turned on.
• 🔊 No click when power is applied.

What to do if the new relay burns out immediately?

This indicates problems in the compressor or electrical circuit. Possible reasons:

• 🔄 Interturn short circuit in the compressor windings.
• ⚡ Breakdown on the housing (check the resistance between the compressor housing and the terminals).
• 🔌 Unstable voltage in the network (a stabilizer is needed).

In this case, a comprehensive diagnosis is required, which is better to entrust to a specialist.

Where to buy the original relay for Bosch?

Original relays can be purchased:

• 🛒 In official service centers Bosch.
• 🌍 On spare parts websites: Emaster, All-Zap, 220-Volt.
• 🏬 In electronics stores (for example, Chip and Dip).

Before purchasing, check exact model of the refrigerator i relay code (on the body of the old relay).

Can a refrigerator operate without a relay?

No, a relay is a mandatory element of the circuit. Without it, the compressor either will not start or will burn out due to overload. In extreme cases, you can temporarily connect the compressor directly (bypassing the relay), but this is dangerous and only permissible for diagnostics for a few seconds!