The situation when you open the refrigerator door and there is room temperature inside always takes you by surprise. First of all, attention is drawn to the absence of the usual hum of a working unit. Silence in the kitchen combined with warming food is a sure sign that compressor has stopped starting or functioning correctly. This can happen suddenly, without preliminary symptoms, or be the result of long-term, but barely noticeable degradation of system components.
However, there is no need to panic ahead of time. The silence of the refrigerator does not always mean that the motor itself has burned out. Often the problem lies in an electrical circuit that simply does not send a start command, or in a simple power surge. Understanding why the refrigerator motor does not workwill allow you to save time and possibly a significant amount of money if the breakdown turns out to be minor. In this article we will analyze in detail all possible scenarios, from simple to complex.
It is important to note right away: if you hear a click, but the motor does not start, or, conversely, hums, but does not pump freon, these are different diagnoses. Electric motor is the heart of the system, but without "nervous system" (relay, thermostat) it will not work. We will look at each element of this circuit so that you can accurately determine the source of the problem.
Primary diagnostics and checking the power supply
Before disassembling the back panel and grabbing a multimeter, it is necessary to exclude the most obvious causes. Sometimes the answer to the question “why the engine doesn’t work” lies on the surface. Check if the light inside the chamber lights up when the door is opened. If there is light, then there is voltage in the outlet, and the problem lies inside the refrigerator itself. If the lights in the entire apartment have gone out or the circuit breaker has tripped, check the switchboard.
Often users forget about such trivialities as an oxidized plug contact or a damaged power cord. Carefully inspect the cable along its entire length: there are no signs of overheating, melting or pet teeth. If everything is visually intact, try plugging the device into another, known-to-be-good outlet. Surge protectorto which the refrigerator is connected could also have failed, ceasing to pass current.
⚠️ Attention: Never try to turn on the refrigerator if you see sparking in the outlet or smell a burning smell from the power cord. This is a direct threat of short circuit and fire. First, replace the damaged element.
If there is power, but the motor is silent, listen. Does the refrigerator make any sounds? A quiet hum, turning into a click and fading, or a complete absence of sounds are key markers for further diagnosis. The absence of any sounds more often indicates a break in the control circuit, while clicks indicate an attempt to start.
Malfunctions of the starting relay
One of the most common reasons why it does not start compressoris the failure of the starting relay. This small element is responsible for supplying a starting pulse to the motor winding. If the relay is “stuck” or burnt out, the motor receives power, but cannot spin up, which is why the protection is activated and a characteristic shutdown click is heard.
You can check the relay visually and by ear. If you remove the back cover and see that the plastic housing of the relay has turned black or melted, the diagnosis is obvious. Also often the bimetallic plate inside breaks or the coil burns out. In some models, the relay can be gently shaken: if something rattles inside, it means the mechanism is damaged and requires replacement. This is a consumable material that lasts on average 5–7 years.
Replacing a relay is a relatively simple procedure, but requires precision. It is necessary to buy a similar part, since they differ in the type of compressor and power. After installing the new element, the circuit is closed and the engine should start. If the new relay also does not help, the problem is deeper - perhaps the motor itself has already been damaged.
How to check the relay with a multimeter?
To check, remove the relay and ring the contacts. The coil resistance should be within normal limits (usually 30-60 Ohms), and the contacts should close when rocked. If the device shows an open or short circuit, the part is faulty.
Problems with the thermostat and sensors
The thermostat (or thermostat) is the “brain” that commands the refrigerator to turn on when the temperature in the chamber rises above the set one. If this sensor is broken in the open position, it simply does not send a signal to start the engine. As a result, the refrigerator remains plugged in, the light is on, but the compressor is silent, and the food begins to deteriorate.
In modern models with a system No Frost and electronic control, air sensors and thermistorsare used instead of a mechanical thermostat. Their malfunction often leads to the control module “thinking” that the chamber is already cold and does not start the cooling cycle. Diagnostics of such systems requires special equipment, since it is necessary to read the resistance of the sensor at a certain temperature.
Sometimes the problem is solved by simply turning the thermostat knob from one extreme position to another. If the contact was simply oxidized, this may help. However, if after this manipulation the engine does not start, most likely the sensor has failed and requires replacement. In electronic systems, the control board itself can also “glitch.”
Interturn short circuit of the motor windings
This is one of the most serious and expensive problems. Electric motor consists of a copper winding coated with an insulating varnish. Over time, due to overheating, power surges, or simply aging, the insulation can deteriorate. A short circuit occurs between the turns, and the motor either stops starting completely or begins to work with overload, quickly heating up.
It is difficult, but possible, to diagnose an interturn short circuit at home. When such a motor is turned on, it often knocks out the circuit breaker (plugs) in the apartment. If the machine is stationary, the engine may hum and try to start, but is immediately turned off by the protection. Measuring the resistance of the windings with a multimeter can show abnormally low values, but an accurate diagnosis is often made only after opening the motor or replacing it.
Repairing the motor by rewinding the windings is not economically feasible in modern conditions. The cost of labor and materials often exceeds the price of a new compressor. Therefore, when the interturn closure is confirmed the compressor unit is completely replaced followed by filling the system with freon.
| Symptom | Probable cause | Complexity repair |
|---|---|---|
| Clicking and silence | Start relay or jamming | Low / Medium |
| Complete absence of sounds | Thermostat, wiring, module | Medium |
| Humming and shutdown | Stuck or shorted | High (replacement) |
| Knocks out machines | Short circuit in motor | High (replacement) |
☑️ Diagnostics before calling a technician
Mechanical compressor wedge
Sometimes the electrical part the engine is working properly, voltage is supplied, the relay works, but the motor rotor physically cannot turn. This phenomenon is called "wedge". It occurs due to wear-out of rubbing parts, metal shavings entering the cylinder, or, more often, due to thickened or coked oil. The refrigerator compressor works for years without maintenance, and the lubricant life is not endless.
When trying to start, a jammed motor consumes a huge current, which leads to strong heating of the windings and tripping of the thermal protection. You hear a humming noise, which after a few seconds is replaced by a shutdown click. Repeated starts can finally finish off the engine by melting the insulation. In some cases (rarely), the method of “swinging” by applying increased voltage helps, but this is a risky procedure.
⚠️ Attention: Attempts to “swing” a jammed compressor on your own without experience can lead to a fire or complete failure of the unit. If the engine hums and heats up, but does not spin, it is better to stop.
To eliminate the wedge, the compressor must be replaced. The old unit, even if it can be temporarily revived, will not survive for long, since the mechanism is physically destroyed. In addition, when wedged, the freon circulation system often suffers, which will need to be cleaned.
Faults in electrical wiring
Do not discount the condition of the internal connections. The vibration that inevitably occurs during compressor operation affects the wires for years. Contacts may become loose, oxidized, or frayed. This is especially true for places where wires are soldered to the terminals of the compressor and thermostat.
Oxidation of contacts leads to an increase in resistance in the circuit. The current passes with difficulty, there is not enough voltage to start the motor. Visually, this may appear as a dark coating on the terminals or melted insulation at the connection point. Simply cleaning the contacts and securely fixing them sometimes works wonders, bringing the refrigerator back to life.
It is also worth checking the integrity of the wires going to the fan (in No Frost models). If the fan is not running, the system may prevent the compressor from starting to prevent the evaporator from freezing. A broken fan wire is a common reason for the entire cooling system to stop.
When you need to call a professional technician
There is a fine line between repairs that you can do yourself (replacing a relay, thermostat) and complex interventions that require a license and equipment. If the diagnostics showed that it itself is faulty compressor, or the problem lies in a freon leak, you cannot do without a technician. The system is sealed, and to open it and solder you need a tool and gas.
In addition, if you are not confident in your abilities when working with 220V electricity, it is better not to risk it. A mistake can cost not only your refrigerator, but also the safety of you and your loved ones. A professional technician will conduct a full diagnostic, check the current consumption and pressure in the system, which cannot be done without instruments.
Independent repairs can lead to loss of warranty (if it is still valid) or the occurrence of new, more complex breakdowns. If after replacing simple parts (relay, sensor) the problem does not go away, entrust the matter to a specialist.
Is it possible to restore a jammed compressor?
Theoretically, there are methods of "swinging" high voltage, but in practice this rarely helps and does not last long. Mechanical damage will not go away, and the motor will soon jam again or burn out completely.
Why is the new compressor louder than the old one?
Modern motors may have a different acoustic profile. In addition, if the system was not thoroughly purged during replacement, combustion products of old oil could remain in it, which affects operation.
How long does a refrigerator engine last?
The average service life of a high-quality compressor is 10–15 years. However, with frequent power surges, overheating or lack of freon, this period can be reduced to 5-7 years.