Quick answer and safety
The compressor is the pump of the refrigeration system. When it fails, a refrigerator typically stops cooling, even though the lights and some fans may still work. However, several less costly parts can produce very similar symptoms, so a compressor diagnosis should come last, not first.
Safety notes:
- Unplug the refrigerator before touching any electrical component or panel.
- The compressor is part of the sealed refrigerant system. Opening it, or working on refrigerant lines, requires professional training and, in many countries, certification. Do not attempt it yourself.
- Many modern refrigerators use flammable refrigerant. Never pierce or cut any tubing.
Symptoms of a failing compressor
- No cooling while the interior light and fans work.
- Clicking, then shutting off, every few minutes. This can be the overload protector or start relay cutting power when the compressor fails to start.
- A silent unit. You do not hear or feel the compressor running at all.
- Running continuously without reaching temperature.
- A hot or very noisy back of the fridge, including loud humming, buzzing or knocking.
- A tripped breaker when the fridge tries to start.
None of these alone proves the compressor is bad.
Rule out look-alike problems first
Check these before blaming the compressor:
- Dirty condenser coils. Heavily clogged coils can cause overheating and poor cooling. Unplug the unit and clean them. See our fridge not cooling guide for steps.
- Condenser or evaporator fan failure. The compressor may be fine while air is not moving.
- Defrost problems. A frosted evaporator can make the fridge warm while the compressor runs. See refrigerator defrost system failure.
- Start relay or overload protector. These small parts help the compressor start. When they fail, the symptoms resemble a dead compressor.
- Control board or temperature sensor. If the board never tells the compressor to run, nothing cools.
- Temperature settings or demo mode. Check the controls.
If you are unsure whether the fault is in the condenser or compressor, see condenser vs compressor in a refrigerator.
The click-and-stop pattern and the start relay
A compressor that tries to start, clicks, and shuts off after a short time may have a weak start relay (or a start capacitor on some models), or it may be mechanically seized. The relay is mounted on the side of the compressor and is replaceable, but it is best left to a technician. Unplugging the fridge is not enough on its own: a start capacitor can hold an electrical charge after the power is off, and it must be discharged by a qualified person. For that reason, leave the relay, capacitor and compressor-terminal work to a technician. If a new relay does not change anything, the compressor itself may be at fault.
What a technician checks
A technician may:
- Check power supply and voltage at the compressor terminals.
- Test the compressor windings with a meter, and test for a short to ground (a winding connected to the metal housing indicates internal failure).
- Test the relay, overload protector and capacitor.
- Check whether the system has a refrigerant leak or restriction.
- Look at the control board and fan operation.
Meter tests on compressor terminals involve electrical hazards and are best left to a qualified person.
Can a compressor be repaired?
A compressor is sealed, so it is not repaired in the way a motor on a fan might be. If it has failed internally, the usual repair is replacement. That involves recovering refrigerant, cutting and brazing lines, evacuating and recharging the system, and is a specialist job. (Our ice machine refrigerant type guide explains why refrigerant must be recovered by certified technicians, and much of it applies to fridges and freezers too.) It is also often expensive relative to the age and value of a household refrigerator. Costs vary a great deal by region and model, so ask for a written quote.
If the issue is the relay, capacitor, overload protector, fan or board, those are separate parts that can be repaired much more economically.
Repair or replace the refrigerator?
Consider these factors:
- Age. If the unit is old and nearing the end of its typical life, replacement often makes more sense.
- Quote versus replacement cost. Many people replace when a major repair is a large share of the price of a comparable new fridge.
- Overall condition. Seals, controls and other parts that are also worn raise the likelihood of more repairs.
- Warranty. Check whether the compressor has a longer warranty than the rest of the refrigerator. Some manufacturers offer extended coverage on the sealed system. Check your documents.
How long should a compressor last?
Household compressors can often last many years, and refrigerators commonly give a decade or more of service, but lifespan varies with usage, cleanliness of coils, power quality and the model. Keeping the condenser coils clean and giving the fridge space for airflow tends to reduce the strain on the compressor.
Can I fix a fridge myself?
Many causes of poor cooling are within reach for a careful homeowner: resetting controls, cleaning coils, clearing vents, replacing a door gasket or a fan. Compressor and refrigerant work are not. If a basic check does not solve it, contact a technician rather than proceeding into electrical or sealed-system work.
To reset the temperature, adjust the control to the recommended setting (often about 37°F or 3°C for the fridge, 0°F or -18°C for the freezer), and give the unit many hours to stabilize. Unplugging for several minutes can also clear minor electronic faults.
When to call a professional
Call a technician if the fridge clicks and shuts off repeatedly, if the breaker trips, if you smell burning, if you suspect a refrigerant leak, or if basic checks do not restore cooling. Move perishable food to another fridge or a cooler while you wait, and follow food safety guidance when deciding what to keep.