Refrigerator Compressor Troubleshooting (Troubleshooting Guide)

On this page

Quick answer
Confirm the symptom
Tools and prep
Step-by-step troubleshooting
Common causes table
Parts matching
When to call a pro
FAQ
Related guides

Quick answer

If your refrigerator compressor isn't running, first unplug the unit and check the power supply. Test the start relay and compressor contactor for continuity. Replace faulty components if they fail the test.

Confirm the symptom

Refrigerator not cooling
Compressor not humming or running
Condenser coils are warm but no noise from the compressor
Freezer is frost-free but refrigerator is warm

Tools and prep

Multimeter
Screwdrivers (flathead and Phillips)
Owner's manual for the refrigerator model
Safety gloves and goggles
Work light with clamp
Plastic putty knife for insulation

Step-by-step troubleshooting

Unplug the Refrigerator
Do: Turn off the circuit breaker or unplug the unit to ensure safety.
Observe: The refrigerator is completely powered down.
Means: Prevents electrical shock during testing.
Next: Check the power supply
Check the Power Supply
Do: Verify the outlet is working with another appliance and ensure the breaker hasn't tripped.
Observe: Outlet is functional and breaker is on.
Means: Rules out external power issues.
Next: Test the start relay
Test the Start Relay
Do: Use a multimeter to test the start relay for continuity.
Observe: Multimeter shows no continuity or erratic readings.
Means: The start relay is likely faulty.
Next: Replace the start relay
Test the Compressor Contactor
Do: Use a multimeter to test the compressor contactor for continuity.
Observe: Multimeter shows no continuity or erratic readings.
Means: The contactor is likely faulty.
Next: Replace the contactor
Check the Compressor Windings
Do: Test the compressor windings with a multimeter for continuity.
Observe: Multimeter shows no continuity or resistance outside the normal range.
Means: The compressor may be burned out.
Next: Replace the compressor
Inspect for Frost or Ice Buildup
Do: Look for excessive frost or ice on the evaporator coils.
Observe: Frost or ice buildup is present.
Means: A defrost system issue may be preventing proper cooling.
Next: Check the defrost components
Check the Defrost Components
Do: Test the defrost timer, defrost heater, and defrost thermostat for functionality.
Observe: One or more components are not working properly.
Means: Defrost system failure can prevent proper cooling.
Next: Replace faulty defrost components
Reassemble and Test
Do: Reconnect all components, plug in the refrigerator, and monitor for proper operation.
Observe: The refrigerator cools properly and the compressor runs as expected.
Means: The issue is resolved.
Next: Monitor for a few hours

Common causes

Cause	Likelihood	Difficulty	Part often needed
Faulty Start Relay The start relay sends power to the compressor. If it fails, the compressor won't start.	Common	Easy–Medium	Start Relay
Failed Compressor Contactor The contactor controls power flow to the compressor. A failed contactor stops the compressor from running.	Common	Easy–Medium	Compressor Contactor
Burned Out Compressor A failed compressor winding or overheating can cause the compressor to stop working.	Sometimes	Hard	Compressor
Defrost System Failure A malfunctioning defrost system can prevent proper cooling and cause the compressor to work inefficiently.	Sometimes	Medium	Defrost Kit
Blocked Airflow Dust or debris on the condenser coils can restrict airflow and cause the compressor to overheat.	Sometimes	Easy	None
Thermostat Issues A faulty thermostat may not signal the compressor to run when needed.	Rare	Easy	Thermostat
Power Supply Issues An unstable or interrupted power supply can prevent the compressor from starting.	Rare	Easy	None
Incorrect Temperature Settings Improper settings can make the refrigerator appear to have a cooling issue when it's functioning normally.	Rare	Easy	None

Parts matching

Match your refrigerator model to the correct replacement parts using the following guidelines:

Identify the refrigerator model number from the owner's manual or a label inside the unit.
Cross-reference the model number with the manufacturer's website or a parts database.
Ensure the replacement part matches the original part number for compatibility.
Check for any specific installation instructions for the part.
Purchase the part from a reputable supplier or the manufacturer.

If unsure, consult a professional technician to ensure the correct part is selected and installed safely.

When to call a professional

The compressor shows no signs of power or operation after testing.
You're not comfortable working with electrical components.
The refrigerator is under warranty and you don't want to void it.
The issue persists after replacing all suspected parts.
There is a strong burning smell or visible damage to the compressor.

FAQ

Can a refrigerator compressor be repaired?

In most cases, a failed compressor cannot be repaired and must be replaced. However, some issues like a faulty start relay or contactor can be fixed without replacing the entire compressor.

How long does a refrigerator compressor last?

A refrigerator compressor typically lasts 10–20 years with proper maintenance. Frequent cycling or poor maintenance can shorten its lifespan.

Why is my refrigerator making a loud noise but not cooling?

A loud noise with no cooling could indicate a failing compressor, a loose component, or a refrigerant leak. Check the compressor and other components for damage or wear.

What is the cost to replace a refrigerator compressor?

Replacing a refrigerator compressor can cost $200–$500 for the part and $150–$300 for labor, depending on the model and technician rates.

How do I know if the start relay is bad?

A bad start relay may produce a clicking sound, fail to start the compressor, or show no continuity when tested with a multimeter.