95 blazer only blows air out of defroster vent and under dash vents

i have a 95 blazer that only blows air out of the upper and lower vents.
ive replaced the control swith checked the vacuum lines, every thing seems ok. the vacuum line to the intake was burned and off, but i think i put it on right. were exactly does it go i went behind the distributor and felt a little tube that think was it. does that sound like the right location

Did you check the line at the vaccum tank? Should be mounted to your hood and a vaccum line attached to it.

the tank has the vacuum line connected.