Can someone please tell me where to vacuum line that control the air vent in the dash of a 1989 Tram Am TBI are located I know one is going to the Heater control valve where does the other one goes that coming from the back of the TBI

 

There's about 6 or 7 lines on the selector valve in the AC control head. 2 of them end up under the hood if you have one of the cars with a heater control valve, which yours evidently does. (different years & models might either have it or not) About 4 of them stay in the interior; they go to the vacuum motors (diaphragms) for things like the defroster, floor duct (heater), dash vents, and Recirculate (Max AC). One of the underhood ones controls the heater control valve, only allowing hot water to flow in the heater core when it's needed. The other one under the hood is the vacuum "supply" that brings the vac to the selector valve, which then sends vac as needed to all the vacuum motors (diaphragms) to control all the airflow doors. That comes from the intake manifold after passing through the check valve and being buffered by the reservoir.

 

FYI. I found a place to purchase like new multi-function vacuum heater control valve, see link below. Mine was exactly right and works perfectly - http://www.top-downsolutions.com/ind...product_id=272