I've been pouring over the van and multiple sources of vac diagrams online and pieced this together, added explanations and pretty color coding. I am fairly sure it's right, although on my van the !@#$ accessory fast idle actuator keeps coming on as soon as the engine is started. Please feel free to check my work, my van was a mess of incorrectly connected hoses when I got it so I have no true reference other than my own understanding of how it's SUPPOSED to work and what I see in these diagrams:
