92 hvac vacuum hoses

[Levi1a]

Hey all. New member here. I am looking to see if anyone has a pic of the two vacuum hoses on the passenger side firewall. From what I have found the grey hose goes to the water shut off valve , but where does the black one go? I don't see a t on the main vacuum hose from the pump. Any help would be great.

 

[dodgenstein]

The black line runs across the firewall and into a fitting on the brake booster.