Where does this line go?
 

I have a single line coming out of the firewall. It looks like a hard rubber vacuum line (black with white stripe?). Any ideas on where it goes?

Re: Where does this line go?
 

Check the bottom of the vacuum reservoir; it may have another nipple on the bottom.

Re: Where does this line go?
 

Correct. It appears to have broken off inside the factory plastic angle fitting on the bottom of the vacuum canister on the passenger side firewall. Looks like I will have to come up with a homemade fix for that.