Quick Summary: A refrigerator that's not cooling is typically caused by dirty condenser coils, a failed evaporator fan motor, a defrost system fault, a faulty start relay, a bad thermostat, or — in the worst case — a failed compressor. Most repairs cost $90–$350. Our $65 diagnostic fee is waived when you proceed with repair.
When your refrigerator stops cooling, every hour matters — your groceries can spoil within 4 hours in a refrigerator that's not maintaining temperature. This guide covers all 9 causes for every major brand, including Samsung, LG, Whirlpool, GE, Bosch, and Frigidaire.
Cause 1: Dirty Condenser Coils Maybe DIY
Condenser coils release the heat removed from inside your refrigerator into the air of your kitchen. When these coils are coated in dust, pet hair, and debris, they can't release heat efficiently. The result: the refrigerator runs almost continuously but can't cool the interior to the target temperature.
Where Are the Condenser Coils?
- Bottom-mounted (most common, post-2000 fridges): Located behind the kick plate at the bottom front of the fridge. Access by removing the grille.
- Rear-mounted (older models): Large black coils visible on the back of the refrigerator.
How to Clean Condenser Coils
- Unplug the refrigerator or turn off the circuit breaker.
- Remove the kick plate (bottom grille) — usually snaps or screws off.
- Use a condenser coil brush (available at hardware stores, ~$10) and a vacuum to remove dust and debris from the coils.
- Clean the condenser fan blades while you're in there.
- Replace the grille and restore power.
Cleaning condenser coils every 12–18 months is the single most impactful maintenance task you can perform on a refrigerator. Homes with pets should clean more frequently — pet hair dramatically accelerates coil clogging.
Cause 2: Evaporator Fan Motor Failed Professional
The evaporator fan circulates cold air from the evaporator coils (located in the freezer compartment) throughout both the freezer and refrigerator sections. When this fan motor fails, the freezer may remain cold (since it's adjacent to the evaporator coils) while the fridge section warms significantly.
Classic Sign: Freezer Cold, Fridge Warm
This symptom pattern — freezer at temperature, fridge section 10–15°C above target — is almost always caused by the evaporator fan. The frozen food in the freezer acts as a thermal mass and stays cold for many hours even without the fan, while the refrigerator section quickly warms without circulating cold air.
How to Confirm the Evaporator Fan Has Failed
- Open the freezer door. You should be able to hear the evaporator fan running. If the freezer is silent when it should be cooling, the fan may have stopped.
- Most refrigerators stop the evaporator fan when the door is opened. Press the door switch to simulate a closed door while briefly holding the door open — you should hear the fan start.
- If the fan motor is seized, you may hear a humming or buzzing sound from inside the freezer with no airflow.
Cause 3: Defrost System Failure Professional
All frost-free refrigerators run automatic defrost cycles (typically every 6–12 hours) to melt frost that builds up on the evaporator coils. The defrost system consists of a defrost heater, defrost thermostat, and defrost timer or control board. If any component fails, frost accumulates continuously on the evaporator coils until they are completely iced over — blocking all airflow.
How Defrost Failure Causes a Warm Fridge
As frost builds up over days or weeks, it acts as insulation on the evaporator coils and eventually blocks the passages through which cold air flows to the refrigerator compartment. The progression is: fridge gets slightly warm → frost accumulation accelerates → fridge warms noticeably → eventually the freezer warms too.
Signs of Defrost System Failure
- The cooling problem developed gradually over several weeks
- Visible frost or ice on the back wall of the freezer compartment (indicates abnormal frost buildup)
- The evaporator fan sounds muffled or you can barely feel any airflow from vents
- Temporarily unplugging the fridge for 24 hours restores cooling (because the ice melts during the outage) — this is a strong diagnostic indicator of defrost failure
Fridge not cooling? Don't wait — food spoils fast.
$65 diagnostic · 90-day warranty · $40 OFF your repair · Same-day available
Cause 4: Failed Start Relay Maybe DIY
The start relay is a small component that helps the compressor motor start. When it fails, the compressor can't start — and without the compressor running, no cooling happens at all. The refrigerator will appear completely dead (no cooling, though lights and fans may still work).
How to Test the Start Relay
- Unplug the refrigerator.
- Pull the refrigerator away from the wall and locate the compressor (a large dome-shaped component at the back bottom).
- The start relay is the small component plugged into the side of the compressor.
- Remove the relay and shake it — if you hear a rattling sound, the relay has failed. A good relay is silent when shaken.
- A replacement relay costs $15–$35 and is a straightforward DIY repair if you can access the compressor area safely.
Cause 5: Faulty Thermostat or Temperature Control Board Professional
The thermostat (or temperature control board on electronic models) tells the compressor when to turn on and off based on the interior temperature. A failed thermostat may fail closed (compressor never turns on) or fail open (compressor runs constantly). Either way, the result is a refrigerator that can't maintain the correct temperature.
Mechanical Thermostat vs. Electronic Control Board
- Older models (pre-2010): Use a simple mechanical thermostat — a metal sensing tube that expands and contracts with temperature. These can be tested with a multimeter.
- Modern models: Use an electronic control board with thermistor sensors. The board reads sensor temperatures and controls all cooling components. Diagnosis is more complex and requires specialized testing.
Cause 6: Damaged Door Gaskets DIY
The rubber door gaskets create an airtight seal when the refrigerator door is closed. If gaskets are torn, cracked, warped, or simply not sealing properly, warm air constantly infiltrates the refrigerator, forcing it to run almost continuously and still fail to maintain temperature.
How to Test Your Door Gaskets
- Paper test: Close the door on a piece of paper. Pull the paper out — it should resist. If it slides out easily, the gasket isn't sealing at that point.
- Visual inspection: Look for visible tears, gaps, mould, or areas where the gasket doesn't sit flush against the door frame.
- Light test: In a darkened room, shine a flashlight inside the closed fridge. If you can see light leaking through the door edge, the gasket isn't sealing.
Gasket replacement is a moderate DIY task — the gasket snaps or screws into a channel in the door liner. Replacement gaskets cost $30–$70 depending on the model.
Cause 7: Condenser Fan Motor Failed Professional
The condenser fan (different from the evaporator fan) draws air across the condenser coils and over the compressor to cool them. If this fan fails, the compressor overheats and shuts off on thermal overload — causing intermittent or complete cooling failure.
How to Identify a Failed Condenser Fan
- Pull the refrigerator out and look/listen at the back bottom. The condenser fan should be running whenever the compressor is running.
- The compressor area may feel very hot to the touch.
- The refrigerator may cool for a while, then stop cooling as the compressor overheats, then resume cooling after the compressor cools down — a cycle of intermittent cooling is a classic condenser fan symptom.
Cause 8: Low Refrigerant / Refrigerant Leak Professional
Refrigerant is the fluid that absorbs heat from inside the refrigerator and releases it outside. Modern refrigerators use sealed refrigerant systems — in a properly functioning unit, refrigerant never needs to be "topped up." If your refrigerator has low refrigerant, it means there is a leak in the sealed system.
Signs of a Refrigerant Leak
- The compressor runs constantly but the fridge barely cools
- Both freezer and fridge are warm, not just one section
- The evaporator coils (visible when you remove the freezer back panel) are partially iced — only part of the coil is frozen, not uniformly
- The problem appeared suddenly rather than gradually
Refrigerant repair requires a certified HVAC/R technician with proper recovery equipment. The refrigerant circuit must be located, repaired, pressure tested, evacuated, and recharged. Sealed system repair is expensive ($250–$500+) and is often not economical on older refrigerators.
Cause 9: Compressor Failure Professional
The compressor is the heart of the refrigerator — it compresses refrigerant and drives the entire cooling cycle. A failed compressor means zero cooling ability. Compressor failure is the most expensive refrigerator repair and often makes replacement the more economical choice.
Signs of a Failed Compressor
- The refrigerator is completely silent — no humming, no cooling sounds at all
- You can hear the compressor try to start (a click) but it immediately shuts off
- Both fridge and freezer are completely warm
- All fans are running but no cooling occurs
Compressor replacement cost: A new compressor costs $200–$500 in parts. Combined with labour ($150–$200), the total repair is $350–$700+. For a refrigerator over 10 years old, most appliance technicians — including ours — will recommend replacement over compressor repair as the more economical long-term decision.
Brand-Specific Notes
Samsung Refrigerators
Samsung French door models (RF series) are the most common cooling complaint we see in Toronto. The most frequent cause is defrost system failure combined with ice buildup in the sealed evaporator compartment — a known design limitation of these models. A forced defrost provides temporary relief; a defrost heater or sensor replacement provides a longer-term fix. See our dedicated guide: Samsung Refrigerator Not Making Ice.
LG Refrigerators
LG French door refrigerators (LRMVS, LRFXS, LRFVS series) are also prone to defrost system failures, particularly the linear compressor models. LG has had compressor issues on certain model years — if your LG fridge is cooling poorly and is under 7 years old, check if your model is covered by any warranty extension programs.
Whirlpool / Maytag / KitchenAid
These brands (all Whirlpool Corporation) are generally reliable but share evaporator fan motor failures as a common weak point on French door models. The start relay is also a common and inexpensive repair on side-by-side models. See our Whirlpool-specific guide: Whirlpool Refrigerator Not Cooling.
GE Refrigerators
GE Profile and GE Cafe refrigerators commonly experience damper control failures, thermistor faults, and evaporator fan issues. See our dedicated guide: GE Refrigerator Not Cooling.
Bosch / Blomberg
These European-brand refrigerators use NoFrost technology and are prone to defrost sensor faults and control board issues when cooling fails. Parts are more expensive than North American brands, but these fridges are generally worth repairing given their high original cost.
Refrigerator Not Cooling — Repair Costs (Toronto 2026)
| Cause | Parts Cost | Total Estimate | DIY Level |
|---|---|---|---|
| Dirty condenser coil cleaning | $0–$10 | $0 (DIY) / $90–$130 (pro) | Maybe DIY |
| Evaporator fan motor replacement | $45–$90 | $120–$200 | Professional |
| Defrost heater replacement | $30–$70 | $120–$200 | Professional |
| Defrost thermostat replacement | $20–$45 | $100–$170 | Professional |
| Start relay replacement | $15–$35 | $15 (DIY) / $85–$145 (pro) | Maybe DIY |
| Door gasket replacement | $30–$70 | $30 (DIY) / $100–$170 (pro) | DIY |
| Thermostat / control board replacement | $60–$200 | $150–$320 | Professional |
| Condenser fan motor replacement | $40–$85 | $120–$200 | Professional |
| Compressor replacement | $200–$500 | $350–$700+ | Professional |
Prices are estimates for Toronto & GTA, 2026. Our $65 diagnostic fee is waived when you proceed with repair. $40 OFF promotion currently applies.