Fault Phenomenon: Putzmeister M56 air conditioner functions normally when cold. After reaching operating temperature (ambient temp 35℃), the AC does not cool, hot air comes from the vents, with no alarm on the dashboard.

Troubleshooting Process:
– Checked AC compressor belt: belt tension normal, no slipping.
– Checked AC refrigerant pressure: pressure normal, no leaks.
– Checked AC condenser fan: fan operates normally, sufficient airflow.
– Measured compressor electromagnetic clutch at operating temperature: found clutch coil slips due to heat.

Root Cause: The AC compressor electromagnetic clutch coil overheats, leading to insufficient engagement force.

Required Parts: AC compressor electromagnetic clutch assembly.