Heater control vacuum

[GMC87]

Well I think I found my problem tonight as to why my defrost vents will not open.
After reading numerous threads on here I starting checking in the engine bay first, and sure enough there was a vacuum line with a tee sitting wide open with no line to it. One end goes into the fire wall by the heater box the other end goes to a funny looking ball thing about double the size of a softball over by the brake booster.

Now I just have to find a good vacuum port to take of of the engine somewhere and verify that that is it.

Kinda figures the truck came from Alabama and had a new engine put in it, i bet they never even gave a crap about hooking it up.