Clicking noise after turning off the HVAC system?

Yep, it sounds like one of the blend door actuators has gone bad at the end of its throw which is common, you will need the follow the sound to be sure but usually it is the mode actuator because it has a harder job to do. Here is the location of the mode actuator so you can check it out and see if it is making the noise. Check out the images (below). Please upload pictures or videos of the problem so we can see what's going on.