I'm having an issue with my 1995 Tahoe. I have very little air coming out of the vents on the dash. I've never thought there was proper air flow out of the vents, but this past week it suddenly got worse. With the blower on high, there is very little air coming out of the dash vents.

Here's what I know:

1. The blower is functioning properly. New blower and wheel in the past year. Works on all speeds.
2. The mode door is functioning properly. I can watch the actuator move from floor, to vents, to defrost. I seem to have more (normal?) air flow on the floor and the defrost, just not the vents.
3. The blend door is functioning properly. I can change the temp from cold to hot, and it appears to work as normal.
4. The recirculation door is not functioning properly. It broke a few years ago, however I have it propped up in the recirc position.
5. A/C is working. I have cold air, just not air flow out of the dash vents.

So what else could cause a blockage or restriction in the dash vents ductwork?

Thanks!

Casey