Ok so I have no heat I no I need to replace the heater but I now no I have a loss of vacuum as well. So I need the vacuum diagram I tried autozone to find and that did not work so if anyone has a pic of the vacuum diagram send it my way I'd prefer not to pay gm thanks

 

Vacuum diags are on here somewhere, use the function.

The two are probably related - there is a heater diverter valve in your car under the hood, activated by a vacuum from your heater switches - if the valve is not opened, the hot coolant can't get to the heater core, and thus no heat.

 

Tried the search and it just came up with my thread if u can help me out Id appreciate it

 

OK - behind the TBI unit is main vacuum source. Has a check valve in it, and the line splits - one goes towards driver side, one goes towards pass side.

Driver side runs along fender and goes to the vacuum ball located under the driver headlight (has to get at it from under the car. This 'ball' holds vacuum so that at low vacuum times, there's still vacuum in the system to run the heater controls.

Pass side runs down to the firewall just to the driver side of the heater box, and goes into the firewall there (with a small wiring bundle from the heater box fan) to the heater controls. There's also another vacuum line there that comes out, and goes to the heater diverter valve.

When you switch to HEAT, the controls send a vacuum out to the heater diverter valve that opens the valve, and allows the hot coolant to circulate through the heater core. When you are on any other setting, it closes the valve and keeps the hot coolant from entering the heater core (so there's not extra warm air in the car).

Somewhere, you have a leak. Could be the line in the engine bay from check valve to heater controls, could be bad line at heater controls, could be bad line from heater controls to diverter valve. I guess it could also be a bad check valve as well.

The heater controls have a bunch of colored vacuum lines on the back, and the switch changes the vacuum around from one to another - they often go bad.

Hope that helps. Should be a sticker under the hood showing vacuum routing, but often they get gone.

This thread has a pic of the check valve in it at back of TBI unit:
https://www.thirdgen.org/forums/tpi/...stem-goes.html

This thread has a pic of the heater controls, and mentions which parts go bad - but you can see where the valve is with all the colored vacuum lines:
https://www.thirdgen.org/forums/inte...t-blowing.html

Your right - can't find a pic of the actual vac diagram here - It's posted all the time, not sure why no one ever made a sticky with it. But what I've given you should get you started - I'll post a vacuum diagram if I can find one.