I have no vacuum for my controls so I went looking for the the vacuum tank that is supposed to be a ball shaped object on the left fender under the hood on my 92 Z. Can't find anything except the charcol cannister.

Any place else it might be?

 

Ahh, the elusive "Sphere of Nothingness", a.k.a. "Pooterball", "Dilithium Chamber", "WTF Izzit Ball", or the more mundane, factory term, "Vacuum Reservoir". It should actually be on the outside of the inner fender, well hidden above the wheel well and partially visible through the openings stamped through the inner fender at the LF corner. It is forward and outboard of the washer fluid container.

 

That's a heck of a place to stash it. It must be forward of the horns. I found a small hose coming out of there and it runs back towards the master cylinder and it's plugged with a screw. That may be my vacuum source and why my controls are stuck in defrost. Looks like I have to take the wheel off to get to it

 

I('m not sure if this will work on a Chevy, but on my Poncho, I can remove the fasteners from the lower filler panel for the ground effects and air dams, and flex the filler panel away enough to get good access to the area in question. Look at it from the underside to see if it's a viable option on your's.