Alright, I've searched and can't find a direct answer. In my 96 blazer (4.3 automatic tranny) the a/c only blows out of the defroster and feet vents. Even when I have it set to head vents. I looked under the hood for a vacuum line leak, etc. So I find a line connected to that sphere bolted to the hood on the driver side. That line is then splitted into two, one line going through the firewall and the other is unplugged (just sitting there connected to the splitter, but nothing else). So that is the problem. My question is...where does this line plug in? I'm thinking it may plug into something on the intake, but I can't find a place to plug it in.

 

That line should then plug into the intake if there are no other lines to the vacuum res. To be sure, I'll try to get you a vacuum schematic when I get home from work tonight. Or if another '96 owner with the vacuum res can comment...

 

I happen to have my hood up and the intake manifold/plenum removed at the moment... (I'll post another thread about that in a few minutes)

If the intake manifold is the same as on the '95 4.3 V6, it's on teh passenger side, rear of the intake manifold. Looks like a small pipe fitting sticking off the back side of the cover. Can't see it with the intake plenum bolted into place, but you should be able to reach beck there and feel it.

G'Luck!
Rex S.