Greetings just purchased a new to me 97 and had a question about the climate controls in the cab. It seems the defrost vent and the floor vent work as they should. When I select the control to move the air to blow out the front and bottom on the selector nothing happens. I talked to a dealer and there is vacum to the cab but I'm not sure if it is the vacum on the floor and does anyone have a part # or what it is called? It is held in by two screws and the vacum line goes in the back of it. ?? Thanks for all your help Brian