Why would a 2003 Dodge Ram 1500 not blow air on the floor and if you place it to floor it blows out the defrost only?

VACUUM LINES

I have the same problem with my Trailblazer. I keep reading that is could be the Vacuum lines, or some card that is on the back of the controls.... GOOD LUCK LET ME KNOW IF IT WORKS>>>>

I have an 03 3500 dually and had a similar problem. The vacuum line was disconnected. The vacuum pump is usually on the right side up near the fire wall close to where the a/c ties in.