Welcome to the Forumz! Do you mean a clicking noise? Most likely one of the 3 HVAC actuators. Many threads can be found here about them under various titles of blend door actuators and how to determine just which one(s) for repair. You can also go on youtube for videos on the subject.
Enjoy your ride!
I typed this 1/2 hr after you made your introduction here...must have missed hitting the post reply icon
And yes just like member Intrepid posted about the actuators.