Fresh/Recirculated Air Selector
WARNING: This page is about a different car, the 2001 Hyundai Accent and 2000 Hyundai Accent. However, it is still accessible from the selected car via links, so may be relevant.
Disconnect Black vacuum supply hose to fresh/recirculated air selector. See VACUUM DIAGRAMS . Connect vacuum gauge to Black hose of fresh/recirculated air selector. With selector in fresh air position, vacuum should exist at Black hose. With selector in recirculated air position, vacuum should exist at Black and White hoses. Repair as necessary.