Mark,

You've probably got a vacuum leak in the climate control system.

It's possible the vacuum supply is disconnected, but more likely the diaphragms are leaking.

There are vacuum diaphragms that open and close flaps to direct the airflow. These diaphragms leak all the time on the 960s/V90s.

Be ready for a shock if you get an estimate for replacement! They are hard to get to, and some people like to replace all of them, which means pulling the dash. There is a dual diaphragm that always goes, and sometimes the recirculation door diaphragm, I would only worry about those.

It's really easy to diagnose if you have a vacuum pump. I can give you directions if you are going to try and diagnose it yourself.

3B