This cabin filter captures airborne particles entering the HVAC intake before they reach the operator compartment. It is installed in the filter housing located inside the cab structure, upstream of the blower and evaporator core. A loaded filter restricts airflow, reducing defogging performance and increasing fan strain. The original filter uses the same pleat density and seal geometry as the housing it was designed for, which prevents unfiltered bypass air from entering the cab. On replacement, verify the airflow direction arrow on the filter frame matches the housing markings.