Common fault
Why is my Sub-Zero refrigerator not cooling?
Short answer
Start in the freezer, not the refrigerator.
Why we start there
Ice cream still solid in there, with a fresh-food compartment that has gone warm, rules out the expensive answer straight away: these built-ins cool the two compartments with independent sealed systems, so anything frozen at all is proof the refrigeration is doing its job. That leaves airflow and defrost on the fresh-food side. In Carmel Valley the usual three are a stopped evaporator fan, a defrost heater or thermistor that has quit and iced the coil, and a condenser loaded with dust that cannot reject heat on a warm mesa afternoon.
What happens next
There is a local pattern worth naming, because it changes the diagnosis completely. If the refrigerator holds temperature overnight and through the morning and only drifts warm from early afternoon onward, that is rarely a failed part. It is a condenser without the margin to cope once the room warms up. The mesa side of Carmel Valley runs meaningfully hotter on a summer afternoon than the streets nearer the lagoon, and a coil that would have coasted through a coastal summer runs out of headroom up here. The repair is a cleaning and an airflow check, not a component.
What we check, in order. First the freezer temperature, to confirm which sealed system is involved. Then the fresh-food evaporator: is the fan turning, and is the coil clear or furred with ice. Ice on the coil sends us to the defrost heater and the thermistor. A clear coil with a dead fan is a fan motor. Then the door seal, along the top edge first, because that is where a heavy custom panel pulls the door down. Then the condenser and the grille clearance. Every stage gets an actual reading inside the cabinet rather than a glance at the display, which on these units is often the last thing to notice a problem.
If that matches what yours is doing, say so when you call — it decides which parts come on the van.
Frost kept coming back on the freezer's rear wall days after I chipped the whole lot out by hand. Defrost heater had failed and the gasket had gone soft as well. He said the damp mornings here finish off a marginal seal faster than people expect.
Cubes had been getting smaller and hollower for months and I was ready to pay for a new ice maker. He checked the water first and found it was plumbed into the reverse osmosis tap under the sink. Nothing was actually broken. Slightly embarrassing, mostly a relief.
The wine column read right on its setpoint and the top bottles were still warm to the hand. He put a probe in at bottle level, upper zone was well off, and it came down to the zone fan and a drifted sensor. Two other outfits had told me the display was fine.
Appliance down in Carmel Valley?
Tell us the brand and what it is doing — we can usually name the likely repair before we arrive.
Questions
Answers before you call
Does the refrigerator have to come out of the kitchen to be fixed?
No, and taking it out would be the wrong way to start. The condenser comes forward through the grille, and this equipment is meant to be serviced standing in its opening. Built-ins here sit on engineered plank or large-format tile run tight to the toe kick. We slide one forward only when a water line or rear fitting leaves no choice, over protection.