95 GMC A/C Issue

[70cst10_05]

So I have had this 95 GMC ext. cab 4x4 for a couple weeks now. Tonight and a few other nights I have driven around (I haven't put many miles on it) I've noticed some condensation on the windshield right where the defrost vents are. One thought I had was that the blender actuator might not be quite getting off of defrost and to vent, because I had a slight problem with it not turning to vent. I solved this by just pushing it and it has worked OK since then. Anyway I thought that maybe since there is cold air coming out of the defrost vents that it is cooling the windshield and with the high humidity here in nebraska that it is causing some condensation on the windshield. I use the wipers to get it off but it comes right back almost immediately. I was wondering if anyone else has experienced similar problems and had a remedy for it. Thank you for all your input. All help is greatly appreciated. Thank you,
Kevin