A freezer that runs constantly but cannot get cold is failing to move heat, and there are only four places that happens: heat is leaking in past a bad seal, heat cannot get out through dirty coils, air is not circulating because a fan has died, or the compressor is not running properly. Work through them in that order — the first two are free, and between them they account for most of these calls.
Read this first
- Unplug the freezer before cleaning coils, removing panels, or pulling the start relay.
- The start relay and its capacitor can hold a charge — do not bridge terminals with a tool.
- Move food to coolers or a neighbour's freezer before you start. Food held above 40°F for more than two hours is no longer safe.
- The compressor and condenser run hot enough to burn.
Step by step
Measure the actual temperature
Put an appliance thermometer between two packages in the middle of the load and read it after eight hours, not after ten minutes. A freezer should hold 0°F, and food stays genuinely safe up to about 10°F while slowly degrading in quality. Knowing whether you are at 15°F or 35°F matters: a freezer that is a bit warm usually has an airflow or seal problem, while one sitting near room temperature has a compressor or sealed-system fault.
Check the setting and any recent power event
Check the control dial or digital setpoint. A power outage can reset an electronic control to a default that is warmer than you had it, and mechanical dials get knocked. Set it to the middle of the range rather than the coldest — the coldest setting on many units runs the compressor harder without necessarily getting the cabinet colder. Give any change a full 24 hours to settle before judging it.
Clean the condenser coils
This is the highest-yield step on the list. The condenser sheds the heat pulled out of the cabinet, and dust, lint and pet hair blanketing it means the unit simply cannot reject heat fast enough. Unplug the freezer, pull the rear panel or kick plate, and vacuum the coils thoroughly with a brush attachment and a long coil brush. On chest freezers the condenser is often the tubing bonded to the outer shell itself — in that case, check clearance around the cabinet instead.
Confirm both fans are running
With the unit plugged in and running, listen at the back for the condenser fan and, on frost-free uprights, open the door and listen for the evaporator fan behind the rear interior panel. A dead condenser fan produces exactly the same symptom as filthy coils. A dead evaporator fan means the cold air never circulates, so the coil ices up while the cabinet stays warm. Spin each blade by hand with the power off — any grinding, wobble or resistance means the motor is going.
Check for ice on the evaporator
Remove the rear interior panel on a frost-free unit. A light even frost is normal; a solid slab packed into the fins means the defrost system has failed and air can no longer pass through the coil. If you find that, the freezer is not short of cooling capacity — it is short of airflow, and the fix is in the defrost heater and thermostat rather than anywhere else.
Test the door seal
Close the lid or door on a dollar bill at six points and pull. On chest freezers, check that the lid gasket is not compressed flat and that the lid closes fully — chest freezer lids are commonly held a few millimetres open by an overfilled basket, which is enough to frost the entire cabinet and drive the temperature up. Clean the gasket, and warm any flattened sections gently with a hair dryer to help them recover their shape.
Check the start relay
If the compressor tries to start, clicks, and stops every few minutes — often with the lights dimming briefly — the start relay is failing. Unplug the unit, pull the relay from the side of the compressor, and shake it. A rattle means the internal contacts have burned out. It is a $15 to $45 part and a ten-minute job, and replacing it promptly matters: a relay that keeps stalling the compressor will eventually destroy the compressor itself.
Check the ambient temperature where it lives
This one catches a lot of people with garage freezers. A standard freezer's thermostat senses cabinet air, and in a garage that drops below about 55°F, the thermostat is satisfied and stops calling for cooling — so the compressor never runs and the contents thaw, in winter, in a cold garage. That is not a fault; it is a unit installed outside its rated ambient range. Garage-ready models are built specifically for this. At the other extreme, a freezer in a hot garage or against a heat source will run continuously and still struggle.
What this repair costs
Doing it yourself
$0–$150
Hiring a technician
$150–$900
Prices are general estimates for typical US jobs, not quotes. What you actually pay depends on your appliance's brand and age, the part required, your region, and each shop's labour rate. The DIY figure assumes you supply the labour and buy the part yourself.
Parts you may end up buying
| Part | Install | Typical price | Typical lifespan |
|---|---|---|---|
| Start Relay and Overload | easy | $12–$45 | 8–15 years |
| Door Gasket | easy | $40–$140 | 8–12 years |
| Temperature Control Thermostat | moderate | $25–$90 | 10–15 years |
| Defrost Thermostat | moderate | $15–$50 | 10–15 years |
| Defrost Timer | moderate | $25–$80 | 8–15 years |
| Evaporator Fan Motor | moderate | $40–$130 | 8–14 years |
| Defrost Heater | advanced | $30–$100 | 10–18 years |
| Lid Hinge and Lock | easy | $12–$60 | 10+ years |
Still not fixed
When to call a pro
If the coils are clean, both fans run, the seal is good, the relay is fine and the compressor runs continuously without the cabinet getting cold, the fault is in the sealed system — low refrigerant, a restriction, or a failing compressor. That work legally requires EPA Section 608 certification and typically costs $400 to $900. Weigh that carefully: a new chest freezer starts around $250 and a new upright around $500, so on a unit over eight years old, replacement is very often the better call. Get a written quote before authorising sealed-system work.
More freezer guides
- Freezer Frost Buildup — Diagnose the Defrost System45–90 minutes plus a 24-hour defrost
- Freezer Door or Lid Not Sealing — Stop the Frost at Its Source45–120 minutes
- Freezer Making Noise — Match the Sound to the Part20–60 minutes
- Chest Freezer Lid Won't Open — Break the Vacuum Safely15–45 minutes
- Freezer Won't Turn On — No Lights, No Hum, Nothing30–75 minutes
- Freezer Leaking Water — Find Out Whether It Is Draining or Dying45–90 minutes
- Everything Is Freezer Burned — Find Out Why30–60 minutes plus a 48-hour log