This air conditioning evaporator is the heat-exchange core mounted inside the HVAC housing of the host tractor. It absorbs heat from the cabin air passing over its fins, transferring that heat to the refrigerant flowing through its internal passages. A damaged or corroded evaporator reduces cooling capacity and can allow refrigerant to leak, causing the system to lose pressure and the compressor to cycle erratically. The unit is built to the original geometry so it seats correctly in the housing duct and aligns with the expansion valve and blower assembly. On replacement, the system must be evacuated, the receiver-drier replaced, and the refrigerant charge weighed in per the service specification.