Stock AC mess to clean up

[71meangreenc10]

My GMC has factory air and everything is there except a few vac lines. When I select the lever to heat/defrost nothing comes out of the vents on the top of the dash, heat comes out of the ac vents. I looked under the dash at the controls and there are some vac lines that are plugged. My cables seam to be working and stuff moves on the mechanical side. My question is has anyone redone their factory controls? Where do you start? What lines go where? Go from the panel contol to outside and back. Pics would be great. I will post pics of what is suspect tomorrow.

Thanks

Smitty