Been trying to get my new GTA's dash vents working properly. The problem is that the economy vent part of the heater comes out of the defrost vent and it doesn't switch to the floor vents when the heat is on. But when the ac vent is selected the air comes out of the proper vents. It even comes out on the floor when bi-level is selected. What would cause the economy selections to be stuck on the defrost or winshield vent but not the ac selections? I'm hoping someone has been down this road before and can diagnose the proper spots for me to check first in order to hopefully save a bunch of time. I'm running out of time to get it ready for it's first road trip with me as the owner.

 

do you hear any vaccum leaks comming from the switch.

 

not that I can hear. Is there a seperate line from the switch that operates a mutual flap? Just seems wierd that I have vent, but only when the ac's on. Maybe that's not so strange? Are the vacuum lines from the switch to the heater box diferent colors? I guess that will be the first place I check. I won't have time to tear into it for a few days so I'm trying to learn all I can before I get it apart. Anybody else got any ideas? It seems that for the vent to work on ac and not on economy vent or heat would eliminate a few possibilities and hopefully shine light on a few likely causes. I just don't know myself what they are. And I'm a prof mechanic! But I do work in a volvo spec shop.(lol) But I am loving working on restoring my new GTA.