Why is my Sub-Zero refrigerator not cooling?

The pattern is worth noticing before you call. A unit that runs warm through the afternoon and is back to normal by morning is telling you it cannot reject heat quickly enough during the day. Near the water that is almost always the condenser. Salt in the marine layer settles on the fins, holds moisture, and binds dust and pet hair into a mat that a household vacuum will not lift. A unit that is warm around the clock and never recovering is a different conversation, and that is where the evaporator fan, the defrost circuit and the damper come in.

What happens on arrival, in order. Grille off, condenser inspected, condenser fan turned by hand to feel the bearing. Then a temperature reading taken at the evaporator rather than off the display, because the display reports what the sensor believes and the sensor is one of the things under suspicion. Then the fresh food evaporator itself: is it iced, is its fan turning, does the defrost heater read continuity, is the thermistor within range. Then the damper. By that point the fault has a name, and you get a price before anything comes off the van.

Two things save the food while you wait, and both matter more here than they would inland. Keep the doors closed. A built-in of this quality holds cold for a surprisingly long time when it is left alone, and every opening in humid coastal air adds moisture that ends up as frost on a coil which may already be struggling. And if the house has been shut up for a while, look at the freezer floor for a sheet of ice before you move anything, because a frozen drain frequently turns up alongside a warm fresh food side and it is far better to have both dealt with on one visit.

If that matches what your appliance is doing, say so when you call — it tells us which parts to bring, and most of these are finished in one visit.