on my 91 eddie i have all the vacuum line figured out except where the vacuum goes into the truck for the heater controls i found the line but it has a big end on it. i had a vacuum diagram once but lost it. and the one one the truck shows the emissions stuff does anyone else have a diagram?

 

Usually ,,,,, heater/defroster controls are supplied vacuum from the intake manifold or any place on it. Just look all over any place that is exposed to manifold vacuum and that would provide the necessary supply to operate the controls.

 

I figured it out. The line was suppose to go through the vacuums canister and the line to the air cleaner goes to the intake