What's this noise?

[jseabolt]

One day my wife drove the Explorer and said it was making this clicking noise from the rear of the vehicle. Upon inspection it sounds a vent door opening and closing every couple of seconds. It was coming from what looks like a vent in the rear of the vehicle. After about an hour, it finally stopped. Maybe whatever it was finally broke.

Is there a vent door that recircs air or something in the rear driver's side that is supposed to open when you have the rear A/C on?

Sorry for the poor quality video. I was trying to capture the noise more than anything since you can't see what's going on behind the vent looking piece.

http://vid222.photobucket.com/album...plorer/VID_20150523_125304337_zpsibbyxozi.mp4

EDIT:

Tried the direct video link but it came up "bad web reputation" or something through my company's internet system. it may work otherwise outside. The video is at the bottom of my photo album.

http://s222.photobucket.com/user/turbofiat/library/2006 Explorer?sort=2&page=1

 

[Rcflyer330]

yes there is a rear vent door it switches between the floor and the overhead vents. the button that controls it is the only button by the rear controls. the rear heat and ac always recirculates.

 

[07LTDDSM]

try to avoid switching ventilation direction when ac is running at full blast. its hard on the doors.