1000. Upper seal. A circular disk covered in rubber or plastic with a hole in the center where the edge is sometimes tensioned by a spring that prevents fluid from leaking at the Evaporator Case. A/C Evaporator Core Seal. HVAC Case Seal. Seal between the air inlet Housing and body of the vehicle. AC AND Amplifier; heater Assembly. AIR Conditioning (A/C) Core Case. Gasket. HVAC Air Inlet. Included with: Housing Assembly.