Air recirculation door

a new motor would take care of that , cause the sensing switch(potentiometer) is in the motor assy.. so if the motor runs past the desired position then the switch is bad in the motor pack. if the swicth on the dash was bad then the motor wouldn't move because it thinks it is in the right position and no action is required. i just hope the splines are not stripped on the recerc. door from extended malfunction. - good luck.

I had this same problem. I took out the glove box . remove screw on bar on rh side of box when open. squeeze sides of box in . It will come forward and out. Once inside you will see the flap that is bumping. Up on the Left hand side of it is a small motor assembly that drives this flap. There are 2 screws to remove it , one you can see and the other is up on the top.( small hands would have helped but I got them out). Once the screws were removed the motor part will pull away from the flap. It just couples up with the end of the flap pinion that has 2 flats on it. Disconnect the electrical by lifting the tab. Using a screw driver open up the motor gear unit by lifting all the tabs (good luck not breaking any) and prying along the middle. Once apart you will probably notice a section of the big white gear missing teeth. I lifted that gear up and rotated clockwise so that it went about 200 degrees. Then you have to reassemble and see if the unit will go back in to where the 2 screws hold it. You also want to make sure that you remove all the broken teeth parts.

m2mustang-
Thanks for the fix - rotating the gear 180 solved the problem for me, at a cost of $0.00!
The only thing I would add was that in order to get better access the top screw, I removed the radio head unit. That made it a bit easier, as I did not have the special offset box wrench you mentioned.

I removed the rotary actuator from the left side of the air box after removing the glovebox. There are two screws holding it in. You will need a 1/4" drive ratchet with a 5.5mm socket for the lower screw and a 5.5mm offset box end wrench (easiest) for the upper. Warning: the upper screw will drive you nuts getting it out! It can't be seen but you can feel it. Up-plug the actuator by carefully un-latching the plug assembly with a small screwdriver. Remove the whole assembly. It just slides on the shaft that operates the door.
The problem is inside the actuator. The gears have weak teeth and have probably been stripped of a couple. GENTLY pry the actuator open. There are several assembly snaps that you'll need to be careful not to break off or you will be gluing the halves back together as i did.
The large gear (final output gear) will be missing teeth. Remove it and index the gear 180 degrees re-engaging some fresh teeth to the driver (pinion) gear. If you're off a few teeth in either direction, It won't matter. The motor shuts off with a resistance switch during operation. Re assemble and you're good to go. (At least until they wear out). I saved about $300 over having the dealer replace the motor/actuator.
Eventually, the motor assembly will need replacing. But at least it's a DIY job. Still saving $$$.
Email me ?? m2mustang@yahoo.com