2000 Volvo S80 vent does not blow out air

Do you sometimes feel less air coming out if you are using the recirculation mode? If you do how cluttered is your glove box? If you open the glove box and look deep inside you will see the recirculation door open and close when you hit the button. If you have a lot of stuff in the glove box and you hit the recirculation button the door closes off the fresh air from outside but what happens that now the fan acts like a vacuum and if it picks up a napkin or big piece of paper it will interfere with the airflow. Good way to test this so you gat a better understanding is if you have a regular home fan turn it on full blast. Behinde it grab a sheet of paper and watch how it sucks it and the paper attaches to the back of the fan. Now feel the air flow how it dimishes. Same concept here.