Hello and welcome to Just Answer,
This is a common problem on your astro van. I have created a schematic for you below. Let me know if you have more questions
You might have to in order to see it, but you can feel for it from the outside. just to clarify this is the GM schematic I just highlighted the path so it is easier to see. The vacuum lines run here from the factory.
I can't get through there enough to pull on it though since it is right behind the condenser
Just want to make sure we are on the same page, do you mean Compressor?
If so then yes you can get to from the inside.