The erason I ask is when I put my a/c or anything on to Vent it blows very little out the vents and extremely well out the floor were the heat would normally blow. ANY RECOMENDATIONS?

The vaccum line goes from the engine bay into your Blazer through a skinny hose located at the top middle of your engine bay.

Then under the dash it plugs into the heater box.

If you can't find it PM me (you'll see PM on the bottom left of my comment) and I'll see if I can send you a piture of it. I'm not taking my dash apart for a photo under there, but the hose might still be visible

If you have a a first gen s10, the vacuum line goes to your heater controls first then to your heater box via 3 other lines. Not sure how the set up is on a secong gen s10.