How to properly remove the relay from the compressor of a Bosch refrigerator: instructions with photos and tips

Refrigerators Bosch are known for their reliability, but even they are not immune from breakdowns. One of the common problems is the failure of the compressor start-up relay. This small element is responsible for starting the motor and protecting it from overloads. If the refrigerator suddenly stops freezing, makes clicks without starting the compressor, or works intermittently, the relay may be the culprit.

You can remove the relay from the compressor Bosch on your own - this will save time and money on calling a technician. However, the process requires care: incorrect actions can lead to damage to the contacts or leakage of refrigerant. In this article we will analyze step-by-step instructions taking into account the features of the models Bosch, a list of necessary tools and typical errors. You will also learn how to check the relay for functionality and when it can be repaired and when it can only be replaced.

Symptoms of a malfunctioning compressor relay

Before removing the relay, make sure that it is the problem. Here are the key symptoms:

• 🔊 Clicks without starting: the compressor tries to turn on, but immediately turns off (the characteristic sound of the relay being activated).
• ❄️ Lack of cold: the motor does not start at all, although the light inside is on.
• ⚡ Compressor overheating: the motor body is hot, but the refrigerator does not freeze.
• 🔄 Cyclic shutdowns: the compressor runs for 5-10 seconds and turns off, then tries again.

These signs may indicate other signs breakdowns (for example, thermostat failure or freon leak), but the relay is the first thing worth checking. In 60% of cases of compressor malfunctions Bosch it is the start-up relay that is to blame, and not the motor itself.

If the refrigerator Bosch equipped with an electronic control unit (model series KGE39: or KGN39:), an error E02 or E04may appear on the display, indicating problems with the compressor. In this case, the relay is also suspect No. 1.

Tools and preparation for work

To dismantle the relay you will need:

• 🔧 Phillips screwdriver (usually PH2).
• 🔌 Pliers with insulated handles.
• 📸 Smartphone for photographing the connection diagram.
• 🧤 Rubber gloves (optional, for protection against static electricity).
• 🔦 Flashlight —the lighting in the lower part of the refrigerator is often insufficient.

Before starting work:

Disconnect the refrigerator from the mains (pull out the plug from the socket)|

Get access to the compressor (move the refrigerator away from walls)|

Take a photo of the current connection of the relay (important for reassembly)|

Prepare a container for small parts (screws, springs)-->

The compressor in refrigerators Bosch is usually located at the bottom of the back wall. It is closed with a metal lid or plastic casing. In some models (for example Bosch KAN58:), access to the relay is blocked by a capacitor - it will have to be temporarily removed.

⚠️ Attention: If the refrigerator is connected to the network through a stabilizer or RCD, turn off the power at the distribution panel. Some models Bosch have capacitors that can retain charge even after the plug is turned off.

Step-by-step instructions for removing the relay

The process of removing the relay consists of several stages. Follow the instructions strictly in order to avoid damage.

1. Access to the compressor

Move the refrigerator 50–60 cm from the wall. Remove the bottom decorative panel (if any) - it is secured with latches or screws. In models Bosch Serie 6 the panel can be part of a single casing, which is removed by moving upwards.

Under the panel you will see a compressor - a black cylindrical block with tubes. The relay is located on its side or top and is attached to the motor contacts. Externally, it looks like a small plastic box with wires.

2. Disconnecting the wires

Take a photo of the diagram for connecting the wires to the relay. In refrigerators Bosch usually 3-4 wires are used:

• 🔴 Red/orange —phase (power).
• 🔵 Blue/black —zero.
• 🟢 Green/yellow —grounding.
• 🟤 Brown/white —start winding (if any).

Carefully remove the wires from the relay terminals, remembering their location. In some models (for example, Bosch KSV36:), the wires are secured not with screws, but with clamps - they need to be pryed off with a screwdriver.

⚠️ Attention: Do not pull the wires - they can be fragile due to overheating. If the wire breaks off, it will have to be extended or replaced entirely.

3. Removing the relay from the compressor

The relay is attached to the compressor in two ways:

1. On the latches (more often in new models Bosch Serie 8). Press the latches on both sides and pull the relay up.
2. On the screws (in older models). Unscrew the mounting screws (usually 2 pieces) and remove the relay.

If the relay is “stuck” to the contacts, do not apply force. Treat the joint with industrial alcohol or WD-40, wait 5-10 minutes and try again.

What to do if the relay cannot be removed?

If the relay does not respond even after treating with WD-40, check to see if the compressor contacts are bent. In this case, carefully align them with pliers. Do not use metal objects to pry - this may damage the insulation.

4. Checking the condition of the contacts

After removing the relay, inspect the contacts on the compressor. They must be:

• ✅ Clean (no oxidation or soot).
• ✅ Smooth (not bent).
• ✅ No traces of melting.

If the contacts are damaged, they can be cleaned with fine sandpaper paper (P1000). Severe oxidation or melting is a sign of a short circuit, in which case the compressor may need to be replaced.

How to test the relay for functionality

The removed relay must be tested to confirm its malfunction. To do this you will need a multimeter.

1. External inspection

Inspect the relay body for:

• 🔥 Melting or blackening.
• 💧 Traces of moisture inside (condensation).
• 🧲 Bent or broken springs (in mechanical relays).

If the housing is swollen or cracked, the relay must be replaced.

2. Testing with a multimeter

Set the multimeter to resistance test mode (200 Ohm). Connect the probes to the relay contacts:

If the readings differ from the norm, the relay is faulty. Also check the relay in the “hot” state: connect it to the compressor and try to start the refrigerator. If the relay clicks, but the motor does not start, the problem is there.

Typical mistakes when removing a relay

Even experienced craftsmen sometimes make mistakes that lead to additional breakdowns. Here's what not to do:

• ⚡ Work under voltage: even if the refrigerator is turned off, the capacitors can be charged.
• 🔧 Use unsuitable tools: for example, uninsulated pliers or a screwdriver with a magnetic tip (may damage electronic components).
• 📸 Ignore photographing the circuit: without it, you risk mixing up the wires during reassembly.
• 🔥 Attach force: if the relay cannot be removed, do not tighten it with pliers - this can tear off the terminals.

Another common mistake is checking the relay without taking into account the temperature. In refrigerators Bosch with a system NoFrost the relay may operate differently at low and high temperatures. If you test it in a warm room, the results may not be accurate.

Replacement vs. relay repair: what to choose

In most cases, a faulty relay is easier to replace than to repair. However, there are exceptions:

• 🔧 Repair is possibleif the problem is in oxidized contacts (they can be cleaned) or a weakened spring (it can be bent).
• 🆕 Replacement is requiredif:
• The body or contacts are melted.
• The winding resistance does not meet the standard.
• The relay is mechanical and the spring is broken.

The cost of a new relay for Bosch is from 800 to 2500 rubles depending on the model. Original spare parts are marked with a code that can be found on the body of the old relay (for example, 00643679 for models Serie 4). Analogs from Danfoss or Embraco are cheaper, but may not fit in size.

Installing a new relay and checking operation

Installing a new relay is performed in the reverse order:

1. Install the relay on the compressor contacts (align the grooves or tighten the screws).
2. Connect the wires according to the photo (observe polarity!).
3. Fix the capacitor (if removed).
4. Install the decorative panel.

After assembly:

1. Connect the refrigerator to the network.
2. Listen to how it works relay: there should be one clear click, then the compressor starts.
3. Check whether the motor begins to heat up (after 5-10 minutes the case should be warm).

If the compressor does not start, check:

• The wires are connected correctly.
• Voltage in the socket (should be 220–240 V).
• State of the thermostat (perhaps it opens the circuit).

⚠️ Attention: After replacing the relay, the refrigerator may work intermittently for the first 1-2 hours - this is normal, as the system equalizes the pressure refrigerant. If after 2 hours the compressor has not stabilized, look for another cause of the breakdown.

FAQ: Frequently asked questions about the Bosch refrigerator relay

Can I fix the relay myself?

Mechanical relays (with a spring) can sometimes be repaired: you can clean the contacts or bend the spring. Electronic relays (in models Bosch Serie 8) cannot be repaired - only replacement.

What multimeter is needed for testing?

Any digital multimeter with a measurement mode will do. resistance (up to 200 Ohm). To check the leakage current, you may need a mode 200 mA.

What to do if after replacing the relay the compressor does not start?

Check:

1. The polarity of the wires (phase/zero).
2. The condition of the compressor contacts (they may have oxidized).
3. The functionality of the thermostat (close its contacts directly - if the compressor starts, the thermostat defective).

Where to buy an original relay for Bosch?

Original relays are sold in service centers Bosch, at AliExpress (by part code) or in spare parts stores for household appliances (for example, 220-volt.ru). Delivery time from Europe is 2-3 weeks, from China - up to a month.

Is it possible to temporarily operate the refrigerator without a relay?

No! The relay protects the compressor from overheating. Without it, the motor can burn out in a few minutes. In extreme cases, you can temporarily connect the compressor directly, but for no more than 10-15. minutes for diagnostics.