Most refrigerators make cold in one place and share it between two compartments. That design is why one side can fail while the other seems perfect.
The air comes from the freezer
On the majority of household refrigerators, a single evaporator behind the freezer wall produces all the cold, and a fan pushes some of it into the fresh food compartment through a damper. If that fan stops, or the damper sticks, the freezer stays cold and the fridge slowly warms. Nothing is wrong with the compressor at all.
The other likely cause
A blocked defrost drain or a failed defrost heater lets ice build on the evaporator until air can no longer pass through it. Same symptom, different part. From outside the two are indistinguishable, which is why we measure the compartment differential before quoting rather than guessing.
What you can do before calling
- Check the condenser coils. In this climate they choke with dust and pet hair faster than most people expect, and a choked condenser makes every other symptom worse.
- Listen for the evaporator fan when the fridge is running. Opening the freezer door usually stops it, so listen with the door closed.
- Do not turn the thermostat colder. It will not help and it makes an overworked compressor run longer.
Is it worth repairing?
For a built-in or column refrigerator, almost always. Those units are engineered for twenty years or more and a fan or board is a small fraction of replacement cost. For a freestanding unit past twelve years with a failed sealed system, we will tell you honestly when replacement is the better spend.
