Center vent air conditioning problem

[ttjr]

I am having a problem with the center dash vents. The vents shut off when the fan setting is increased to a high setting and the AC mode is set for the dash. I can hear a flapper door closing but then it will reopen when the fan is turned off. Is there an easy fix for this? I would have to guess that there is an actuator arm that came off???
05 Avalon XLS

[Tom in Tacoma]

Are you using 'Auto' mode? What does the Air Conditioner display show (where the air is being directed) when that happens?

[ttjr]

I can either use auto mode or manual mode. As soon as the airflow through the center vents approaches max fan I hear a thunk, the vents go dead and I hear the fan noise increase. I turn off the fan, I again hear a thunk and can then turn on the fan again with air coming out of the center vents until near max fan the process repeats itself. The LCD shows the air blowing through the vents.

[Tom in Tacoma]

That doesn't sound right... Sounds like you might need to eyeball it.