I have finally got my 86 back on the road after a complete tear down. The final step is to get the A/C going again. My question is, the little black plastic tube that comes through the firewall with the A/C harness goes to the vacuum canister on the bottom of the front fender well correct? If that is so, where is the actual vacuum source coming from? Am I missing another tube somewhere? I can post a pic tomorrow if needed.

 

There is a "T" in that line so that the spherical vacuum canister and the vacuum line going under the dash to the HVAC controls both see vacuum. The source of that vacuum is, obviously, the intake.

There is another post on this board about this that shows this. The "T" is actually a vacuum check valve AND a T all in one.

BTW- there is another vacuum line (longer and with a straight hose nipple on the end, not 90* like the one that goes to the T) coming through the firewall- that goes to your heater diverter valve up near the front of the pass. valve cover.