[BNaylor]

Welcome to AF.

It sounds like you may be missing accessory vacuum. So you might check the vacuum line running from the intake manifold, by the battery and over to the firewall. Inside the cabin around the blower motor will be a distribution block where engine vacuum inputs and then branches off to the various actuators that control the vents and airflow. The climate control provides the electrical signals and commands but vacuum is still used throughout the HVAC system.

One symptom is you will only get airflow out of the floor or defrost vents.