HVAC control problems

I have a 2002 Regal and the air flow direction switch is not functioning properly. No matter where I set it, it blows out all the vents at once- the dash, floor and defroster. Any ideas?

Welcome to AF.

Do you have the manual dual zone or automatic-digital climate control system?

Regardless to start the HVAC system uses engine vacuum to help control the actuators that control airflow and which vents to use. So check the plastic accessory vacuum line that comes off the upper intake manifold or supercharger depending on which engine you have. It routes along the firewall to the area under the main engine compartment fuse box and battery or inner passenger side fender. Check the coupling at the inner fender. From there it goes into the main wiring harness right in to the cabin to under the dash in to a vacuum cannister.

If the above is good then the climate control head unit may need replacement.

I have the digital dual control unit.
I found the plastic line as you stated and it had a hole wore in it near the battery. I cut it and installed a small piece of vacuum hose to splice it back together. HVAC control still not working properly. Is it possible that my problem is the temp door actuator?

Im new here and I have the same exact problem, air to all outlets! No hole in the vacum line, what else could it b? Help!