Fault Phenomenon: John Deere 850K dozer AC vents have low airflow, poor cooling effect.

Troubleshooting Process:
– Checked filter: cab AC filter clogged.
– Checked evaporator: evaporator surface clogged with dust.
– Checked refrigerant: low pressure due to leak.
– Checked compressor: compressor clutch slipping.

Root Cause: The cab AC filter and evaporator surface were severely clogged with mineral dust, resulting in low airflow and poor heat exchange efficiency.

Required Parts: Replace AC filter and clean evaporator.