Start where the failures actually live. Airflow first: a filter past its life, a blower struggling, or returns blocked by furniture starves the coil, drops cooling, and eventually freezes it. A surprising share of no cooling calls end at this step, which is why any diagnosis that skips it and opens with a compressor is out of order.
In La Habra, a no cooling call during the first heat spell is read in a fixed order: filter and airflow, then the condensate drain's safety switch, then charge, then components. The inland heat means the attic half of the system has been baking all afternoon, and readings taken there explain most of what the rooms are reporting.
Electrical second: the capacitor and contactor are the small parts that start big motors, and they fail on the hottest days because that is when they work hardest and longest. Gauges third: refrigerant charge is measured, and low charge means a leak to find, because refrigerant circulates in a sealed loop and is never used up.
Ducts last and often: cooled air dumped into an attic through a separated run cools the attic faithfully while the house complains. If one end of the house never cools while the other overcools, suspect the air's road, not the machine making it.
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