Hello again forum,
My 2010 dodge journey has a distinct knocking or clicking sound coming from behind the glovebox. It only happens right after start-up and stops about 10 seconds or so later. I have determined it to be the re-circulator "door" inside the blower unit mounted right behind the glovebox. This door controls whether or not you get fresh air or recirculated air depending on if you push the button or not. This door is controlled by a small motor mounted on the right side of the blower assembly. I don't know how, but the motor got out of sync with respect to its rotational location and it seemed to be trying to make the door travel past its limit, causing the nasty plastic stripped gear sound at start-up. All I did was remove the motor, turn the key and let the motor rotate on its own. Then I shut the car off, unplugged the motor and re-installed. Put it all back together and all is well. The motor reset its positioning and it works like new. I don't know if it'll happen again but for now I'll take an hour of my time and no parts to fix it any day. Please see photo of location of motor. Note the two screws sticking out from the motor in question. If you plan on tackling this yourself as I did, all you have to remove is the glovebox. Two standard phillips head screws hold the motor in place. Slide it straight off the gear. Good luck!