Clicking noise at HVAC on 99 Tahoe

[Scott_in_AZ]

When I my fan knob switched off at the instrument panel or the recirculating button pushed off I get a clicking noise coming from what I think is the HVAC (black plastic blower found at the front of the cabin on the passenger side by the feet of the passenger).

The clicking stops when I have recirculatin button pushed on and the fan blowing.

Anyone know what I need to do to turn the clicking noise off?

Thanks

[GaryL]

That's a tough one to diagnose over the web, but it sounds like the motor that opens the fresh air door may have stripped a gear and is trying to open the door, but can't.