95 Heater air flow issue

Have a 95 EX that I just bought. The fan comes on at various speeds
correctly (you can hear the different speeds), but there is no air
flowing out of any vents - neither defrost, vents, or leg positions.
Recirc also seems to work okay as the flow sounds considerably louder
when enabled - but again, no actual tangible flow.

I have been told that there is a blockage, but wanted to confirm and get
some idea where to start.

Also, there may be no working A/C, but I don't really care about that
issue yet. I can try a recharge if I can solve problem #1.

Finally, a custom air intake (under hood) was installed by the previous
owner. Don't know if that could be contributing.

Thanks,
John