GM Genuine Parts A/C Evaporator Cores are designed, engineered, and tested to rigorous standards, and are backed by General Motors. These A/C evaporator cores are heat exchangers and are located in the HVAC housing, where they cool and dehumidify the cabin air. Refrigerant is metered into the evaporator by the orifice tube or expansion valve. GM Genuine Parts are the true OE parts installed during the production of or validated by General Motors for GM vehicles. Some GM Genuine Parts may have formerly appeared as ACDelco GM Original Equipment (OE).