When the E36 A/C blows warm, diagnose it in order:
- Watch the compressor clutch with the A/C on — the pulley centre should lock to the spinning outer pulley. If it never engages, suspect a burnt clutch, no power, a blown fuse or the compressor relay.
- If the clutch won't engage, the most common cause is a low refrigerant charge: a leak drops the charge and the low-pressure switch cuts the clutch — confirm on manifold gauges.
- If the charge is normal but it still won't cool, look at the expansion valve — it reads on the gauges as an abnormal high/low split (icing at the valve, the low side pulling toward vacuum): refrigerant present but not metering into the evaporator.
A blinking snowflake on the climate panel means the module detected a fault and switched the compressor off — usually a pressure-switch cut-out, and strongly tied to the well-known climate-module capacitor failure, which is repairable.