What should a mechanic test for no cooling?
A useful test plan for no cooling verifies the operating state first, preserves scan evidence, and measures the competing heating & air conditioning paths before any component is replaced.
Plausible causes
- Cabin HVAC airflow, temperature-control, or refrigerant-system concern
- Airflow or distribution fault
- Heating/cooling production fault
Useful next checks
- HVAC/body/powertrain module scan and PID plausibility
- Blower command/current, filter, doors, evaporator temperature, and drain
- Recover/weigh and approved leak/pressure-temperature testing
- Coolant level/flow, heater-core, fan, and zone-actuator tests
Sources and method
This answer provides hypotheses and a verification plan, not a component verdict. Exact repair procedures require authoritative service information for the specific vehicle.
HVAC System Description and Diagnostics · NHTSA / General Motors