Typically there are three electric actuators for the Heating, Ventilation, Air Conditioning (HVAC) system on that vehicle. An actuator looks like this:
These actuators drive a small plastic door that manages air flow inside your vehicle. There is typically one actuator for the recirculation door (max A/C?), one (or two) for temperature blend (hot / cold) and one for mode control (Defrost, panel or floor output)
Inside that actuator is an electric motor and a gear train. The gear train is made of plastic. Sometimes things get jammed up. Plastic gears get stripped. Additionally, its possible the mate between the actuator and the plastic door gets muffed up.
The noise you are hearing is definitely an actuator gone awry. You can figure out which one by carefully making changes to the settings. An alternative means is to open the glove box, squeeze the sides, open it ALL the way down. Look inside and find each of the actuators. Actually I'm pretty sure there is at least one actuator on the drivers side of the HVAC unit. Place your hand on each until you find which one is making the noise. Replace it. Pray that what is broken is the actuator and not a split inside HVAC case at the plastic door. Been there, done that.
The actuators are relatively inexpensive... but... in some cases you may have to remove the instrument panel to get to it. And that's a big job, not for the casual mechanic.