Why is my Sub-Zero refrigerator not cooling?

What is actually going on

A Sub-Zero built-in runs a separate sealed system for each compartment, so a rock-hard freezer beside a warm refrigerator is good news: the expensive half has proved itself and the fault sits on the refrigerator circuit — its evaporator fan, its defrost, or a thermistor that has drifted. If both compartments are warm and the unit is running constantly, look at the condenser first: in Pacific Beach a coil packed with salt and sand is a cause in its own right.

What we check, and in what order

The freezer first, because that one observation decides everything after it. Then the condenser and its fan through the grille, since a restricted coil in a beach kitchen produces exactly the warm-in-the-afternoon, better-by-morning pattern people describe. Then the refrigerator evaporator: whether the fan is turning, whether the coil is clear or furred with ice, whether the defrost heater has continuity, and whether the thermistor is reporting what the compartment is actually doing.

Ice on the refrigerator evaporator is worth explaining, because it looks like the fault when it is really the result of one. Once defrost stops finishing, the coil grows a jacket of ice that insulates it, and airflow through the compartment falls off week by week. That is why this fault gets described as gradual rather than sudden, and why the display is often still showing a sensible number while the top shelf sits at room temperature.

If that matches what yours is doing, say so when you call — it decides which parts come on the van.