Clicking noise when vent is turned on or car is turned off

bad blend door actuator wont be a problem unless ur heat or ac stop working

I have the same problem. It just started. I see the blend door opening and closing when I switch from outside air to recirculate.It seems like the electric motor keeps turning when the blend door comes down. Clicking noise is in the actuator. "Update". Remove the Glove box. 7mm screws. Remove the lower panel. 3 two piece pastic retainers. Looking through the glove box see Upper far right is the Blend Door Actuator. Used a 1/4 in. swival head ratchet with a 5.5 mm socket, one hand through the glove box and the other hand pushing ratchet up from bottom where panel was removed. With hand through the glove box to guide socket on screw and other hand turning the ratchet, Very Tight area. Remove 2 screws,let actuator drop down. I will remove Electric connection when I am ready to install new actuator. I will be installing new actuator in a few days. Installed New Part # 15844096 AC Delco Made In China,LOL Wholesale $26.20, List $47.64. It was a Bear to get the 2 screws started. Used sewing thread around screws so as not to loose them if they fell out, also applied a little rubbery sticky substance at head or screw to keep them in place. No room to get your hands in place to install screws, but I managed. Did not remove heater Box. All in all the new Actuator is working great. No other parts needed. This solved the problem Bob