1998 Chevy Astro heat and air

U have a broken vacuum line that runs along the intaike manifold ! All u need to repair that is sone vacuum line.
If u look remove the air intaike box from the van & look under the air inlet tube to the throttle body u might see a little black plastic line. That would be the vacuum line. Follow that to ur left & there will be a junction or 1 way valve, the other end on the intake is behind the a/c compressor. It is easier to remove the engine cover from inside the van & on the drivers side u will see it.
I have added a picture, it is not the best but the broken line on the picture it the 1 that is broken !

I hope this helps u !