Clicking noise from heat/AC

Hi,

This is a more than likely a HVAC door actuator. They can click pretty loud but they have plastic gears inside them and when they strip they begin to click. They do this all the time even with the system on or off because it is constantly trying to calibrate it so that it knows where the door is.

The only way to fix it is to replace it. Unfortunately, we need to know which one it is.

Here is the process for each. You can take the panel on the dash off and touch both while it is making the noise to tell which one it is.

Let me know what you find. Thanks