The situation when, after a scheduled defrost, a click is heard in the refrigerator, but the compressor does not start, is familiar to many owners of household appliances. Typically, this sound indicates an attempt by the engine to start, which ends in failure, after which the protective relay is activated. Repeated clicks with an interval of several seconds or minutes - this is a signal that the electrical circuit is closed, but mechanical rotation of the rotor does not occur. Most often, the problem lies not in the defrosting itself, but in the coincidence in time of the end of the defrost cycle and the occurrence of a malfunction in the starting system.
Sometimes users notice that characteristic crackling or clicking sounds appear precisely after the equipment has been left unplugged for a long time. This may be due to the fact that thermostat recorded an increase in temperature and issued a start command, but the system components could not withstand the load. It is important to understand that ignoring these sounds can lead to burnout of the motor windings or failure of the compressor, which will require expensive repairs.
In this article we will analyze in detail all the possible reasons for this behavior of the unit, from simple operating errors to complex technical breakdowns. You will learn how to carry out initial diagnostics yourself and in which cases calling a technician is the only correct solution. It is critically important not to try to force start the refrigerator if it makes a series of clicks and hums without further cooling.
The principle of operation of the start relay and the causes of clicks
To understand the nature of the sound, you need to understand trigger device. In most modern and older models of refrigerators, the compressor is started using a start relay. It is this small element that makes a loud click when the engine is turned on and off. When the thermostat requires cold, it applies voltage to the windings, the relay is activated, starting the motor, and the first click is heard.
If after defrosting you hear a series of clicks, this means that the relay is trying to start the compressor, but the current in the starting winding is rising too quickly or the rotor cannot move. As a result, the thermal relay opens the circuit to prevent overheating, and a second click is heard - shutdown. This cycle can be repeated endlessly until you disconnect the device from the network.
- 🔌 Inductive relay: works due to an electromagnet, which draws in the core when current is applied, closing the contacts.
- 🔥 Thermal relay: contains a bimetallic plate that opens the circuit when the permissible force is exceeded current.
- ⚙️ Posistor: in modern models, the switching function is performed by a semiconductor element, which can also produce quiet clicks or crackles when heated.
A common reason that the refrigerator clicks after defrosting is sticking of contacts or wear of the relay mechanism. If the device stood for a long time without moving, a layer on the contacts could oxidize, preventing the normal passage of current. In this case, the relay hums, clicks, but cannot close the circuit completely, which creates a characteristic intermittent sound.
The influence of the No Frost system and defrost heating element on the start-up
In refrigerators with a system No Frost the defrosting process occurs automatically, but sometimes users perform manual defrosting if the system fails. If after such a procedure the unit begins to click, the problem may lie in the defrost heating element or defrost sensor. These elements are responsible for heating the evaporator to remove ice, and their malfunction can block the operation of the compressor.
When the defrost heating element burns out or, conversely, shorts to the housing, the control system can block the start of the compressor for safety reasons. In some models, the electronics reads the resistance of the heating element before starting the cooling cycle. If the parameters are outside the normal range, the controller does not give a start command, and the relay may make idle clicks when trying to diagnose the circuit.
⚠️ Attention: In models with electronic control, a faulty defrosting heating element can cause the refrigerator to click, but not cool. Do not ignore errors on the display if they appear along with beeps.
It is also worth checking the defrost sensor. If it is “stuck” in the “defrost in progress” position, the compressor simply will not receive a signal to turn on. In this case, the clicks may not come from the start relay, but from the air damper valves or switches, which are trying to change the operating mode, but cannot do so due to a mechanical obstacle or icing.
Diagnostics of the start-up protection relay with your own hands
If you decide to carry out diagnostics yourself, first of all you need to turn off the power to the refrigerator. The start relay is usually located at the lower rear of the unit, next to the compressor, and is covered with a plastic casing. To access it you will need a screwdriver and possibly pliers. Remove the casing and carefully disconnect the wires, remembering their location or photographing the connection diagram.
Remove the relay from its seat on the compressor. It may be a tight fit, so rock it slightly from side to side. Visually inspect the case: if traces of burning, melting or black spots are visible on the plastic, the part definitely requires replacement. Even if there is no external damage, the internal mechanics may have failed.
You can use a multimeter to check the serviceability of the relay. Switch the device to continuity or resistance measurement mode. Check the integrity of the contacts and coil. If the resistance is infinitely high or, conversely, is zero where it should not be, the relay is faulty. Also try shaking the relay near your ear: if you hear a clear knock inside the core being torn off, the part is unsuitable for use.
☑️ Relay diagnostics
Replacing the relay is a simple and inexpensive procedure. The main thing is to purchase a similar model, since they differ in the type of compressor and power. Installing a new element takes a few minutes: just insert it onto the pins of the compressor and connect the wires according to the diagram.
Problems with the compressor: wedge or interturn short circuit
The most serious cause of clicking sounds is a malfunction of the very heart of the refrigerator - the compressor. If after defrosting the unit clicks but does not start, the so-called “wedge” of the motor may have occurred. This is a condition when the piston group gets stuck at a dead center and the rotor cannot turn. At this moment, the starting relay supplies current, a switch-on click is heard, but the motor stands still, the current increases, and the relay turns off with another click.
Another possible reason is an interturn short circuit in the motor windings. During prolonged downtime or a power surge, the insulation of the wires could be damaged. As a result, when you try to start, a short circuit occurs, which instantly knocks out the protection. This problem can be distinguished from a relay breakdown by the nature of the sound: when closing, the click is often accompanied by a sharp buzzing and sometimes sparking in the area of the terminal box.
| Symptom | Probable cause | Character of the sound | Solution |
|---|---|---|---|
| Single click, silence | Thermostat malfunction or open circuit | Silent click | Replacing the thermostat |
| Series of clicks every 10-20 sec | Malfunction of the starting relay | Loud metallic click | Replacement of the relay |
| Click + hum 3-5 sec | Stuck compressor | Low-frequency hum | Repair or replacement of the compressor |
| Crackling inside the chamber | Thermal expansion or ice | Crackling, clicking plastic | Checking defrost |
Attempts to “unwedge” the compressor by applying increased voltage at home are extremely dangerous and often lead to final breakdown of the unit. If diagnostics indicate a problem with the motor, it is better to contact professionals to accurately assess the feasibility of repair.
Is it possible to start a jammed compressor?
There is a method of starting the compressor directly, bypassing the relay, using a special start button. However, this requires skills in working with 220V electricity. If the compressor does not start from the first seconds, the method will not work and may lead to burnout of the windings.
The role of the thermostat and temperature sensors
The thermostat (thermostat) is a device that controls the temperature inside the chamber and gives a command to turn the compressor on or off. If after defrosting you hear clicking sounds, but the refrigerator does not freeze, the contacts inside the thermostat may be burnt or oxidized. In this case, it can close and open the circuit chaotically, preventing the compressor from reaching operating mode.
In electronically controlled refrigerators, temperature sensors are used instead of a mechanical thermostat. Their readings are read by the control module. If the sensor produces incorrect data after defrosting (for example, due to moisture or damaged wiring), the module may block the compressor from starting. In this case, clicks can come from the control module itself or from the damper actuators.
Checking a mechanical-type thermostat is simple: you need to short-circuit the two wires going to it, bypassing the device itself. If after this procedure (while observing safety precautions!) the compressor starts and works, it means that the thermostat is faulty and requires replacement. Remember that during such a test the refrigerator will operate continuously, so you cannot keep it in this mode for a long time.
⚠️ Attention: When working with the thermostat and wiring, make sure that the refrigerator is unplugged. Short-term switching on for testing is allowed only if you have skills in working with electrical appliances.
Operation errors after defrosting
Sometimes the cause of clicks is trivial and related to user actions. After defrosting, the refrigerator should be completely dry. If you turned on the unit while there was still water or condensation inside, moisture could get onto the electrical contacts, causing a short circuit or corrosion. In such cases, clicks may be a sign of insulation breakdown.
Another common mistake is turning on too quickly after defrosting. The refrigerant and oil in the compressor need time to return to operating condition and be distributed throughout the system. If you turn on the refrigerator immediately, the compressor may overload, which will trigger the protection and cause characteristic clicking sounds. It is recommended to wait 2-4 hours after complete defrosting before turning it on for the first time.
It is also worth checking whether the refrigerator is installed correctly. If you move the floor cleaning unit after defrosting, it may not stand up straight. A misaligned position will affect the operation of the compressor and may cause vibrations that are perceived as clicking or knocking. Use a building level to check the horizontal installation.
When you need to call a specialist
Despite the possibility of self-diagnosis of some components, there are situations when, without a qualified a specialist is indispensable. If you have replaced the start relay and thermostat, checked the wiring, but the refrigerator continues to click and does not turn on, the problem most likely lies in the compressor itself or the refrigerant circulation system.
Also, the help of a technician is necessary if the clicks are accompanied by a burning smell, smoke or sparking. These are signs of a serious electrical problem that could cause a fire. Do not attempt to repair complex components, such as a sealed circuit or the compressor itself, without special equipment and knowledge.
A professional diagnostician will be able to accurately determine the cause of the problem using pressure gauges, testers and experience. He will tell you whether it is worth repairing the old refrigerator or whether it is more economically feasible to purchase a new one. Remember that improper repairs can aggravate the situation and make restoring the equipment impossible.
Why does the refrigerator click but does not freeze after defrosting?
Most often this indicates a faulty start relay or compressor. The relay tries to start the motor, but due to a breakdown (sticking contacts, wear) or a problem with the motor (wedge, short circuit), the start does not occur. Also, the cause may be a freon leak, although in this case the compressor usually works for a long time without stopping, and there may be no clicks.
Is it possible to use a refrigerator if it clicks?
It is not recommended to operate a faulty refrigerator. Constant attempts to start (clicking) lead to overheating of the compressor windings and can permanently damage it. In addition, the food in the chamber will begin to deteriorate due to the lack of cold. It is better to turn off the device and carry out diagnostics.
How long should the refrigerator dry after defrosting?
The optimal time for drying and restoring the refrigerant balance is from 4 to 8 hours. The minimum allowable time is 2 hours, but it is better to let the equipment stand longer, especially if the defrosting was complete (until the ice completely melts). Turning on a wet refrigerator is dangerous for electricians.
What to do if, after replacing the relay, the refrigerator clicks again?
If the new relay is working properly, but the situation repeats, then the problem is not in the relay, but in the compressor. Most likely, the motor is “jammed” or an interturn short circuit has occurred in its windings. In this case, a compressor replacement or complex repairs with a motor overhaul are required, which is often not economically feasible.