air vent with no air

recently while i was driveing i noticed that there was no air comeing form the vents , i hear the motor of the vents running and i dont now whats wrong , i think its cloged by something but i aint sure , any sigestions on how to fix it?

you could try my trick. turn the blower to max and start flipping between floor defrost vent and so on… seems like something under the dash could use some fresh oil.

other then that if your brave pull out the dash and rebuild the heater box.