Have you ever had it looked at? how long has it been going on? I hope my AC dosnt go out.Mine does that to, when I go from floor/defrost to floor/forward vent and it clicks for like 20-30 seconds. But If I go to max A/C it will only click 2-3 times. And it still changes the airflow. It doesnt get stuck, just clicks.
I have the same issue. When I shut the vehicle off after a few minutes the clicking starts. I think there is a vent "door" that defualts to a certain postion after the ignition is shut off. The click seems to be from the door trying to close to the defalut postion.mine makes a bunch of noise a couple minutes after i turn the truck off. I got some fast food and parked, turned the truck off and a few minutes later there was all this noise coming from behind the dash. maybe its the same thing.
i have the digital heater functions if that matters. (I cant think of the specific term now) i will have to test this out soon and see if changing the air direction makes that noise.