locating vacuum lines for a/c blower

[Guinevere]

Had some work done on my '97 p/u, but now I don't get any air through the vents into the cab no matter which setting I use. I can feel some air coming thru the defrost vent and at foot level. Possible disconnect of a vacuum line that opens the door to the cab vents? If so, how do I locate the line(s)? I've checked the manual, but no schematic. TIA for any help!!

[NAJ]

Model and Engine Size? What type of work was done?

[Guinevere]

2500 with a 5.7 TD. Had rings and 1 piston replaced, but blower was working fine. Then had the valves adjusted and fuel filter replaced. Now no air with high 90s predicted for the next several days...

[NAJ]

Did you mean 5.9L? 5.7L is a Hemi. PM me your Vin and E-Mail address.