Need help with A/C vent/blower problem

[99GMCZ71]

I have a 1999 Yukon, (old body style) and when you have the A/C on max and the recirculation button is lit, very little air comes out of the vents. Take it off of recirculation and the air comes out of the vents fine. The air goes nowhere else when this happens and all funtions work fine, ie defrost, floor, mix. The recirculation door moves when you hit the button, you can hear the change in the air. The blower motor is fine. Any ideas???

[Cop_Dodger]

Sounds like you've got restricted ducting or the mode door isn't working. Start with easy stuff first. Check on the passenger side under the dash. Look for something blocking the intake duct. It's not uncommon to have a plastic shopping bag get stucked up against the duct.