Noise

I have the same thing on my 2010 and they said it was the AC Blend door motor.

I has the same issue with my 2005 Armada. I was able to fix it through replacement of one of the electric actuators. The clicking that you are hearing is a stripped gear cuasing the acutator yo slip when it tries to close the vent. I found mine by looking under the drivers side to the right of the accelerator pedal. Hope that helps.

JUST HAD MINE REPAIRED ITS CALLED THE A/C ACTUATOR AND THE DEALER CHARGED ME $625. THE PART ONLY COST $45. WOULD COME ON AND STAY ON FOR HOURS.