Undo the Torx screws holding the trim in the driver's footwell.
Unscrew the OBD-II connector from the trim panel.
Locate the left stepping motor (it has a large "L" on it). Unplug the
connector and any other wires in your way. Undo two screws holding the
motor and pull it out.
Make sure the notch on the shaft is pointed upwards. If it's not, plug
the motor connector back in and run the ACC calibration until the shaft
is positioned correctly.
Old style green plastic stop arms often crack at the base, allowing the
shaft to spin freely. Newer style white arms have this end reinforced,
however they sometimes crack at the upper notch instead.
Remove the stop arm. Inspect the yellow shaft, make sure it turns and is
not broken. You can peek through the lower vent, or remove the vent
completely for easier access to the inner part of the shaft.
New vs old
This replacement arm was fabricated by my relative who works at the machine
shop. It's made out of military grade aluminium, very light and strong.
There are similar aftermarket replacement arms sold online.
Install the new arm. It will be seated tight, so push it in carefully -
all the way until the catch clicks. Before re-installing the motor, make
sure the shaft profile is aligned with the notch on the motor shaft.
The passenger side is less prone to failure, but I decided to replace both
as I had extra parts. Start by pulling the clips out of the carpet trim.
Next, undo the four screws holding the lower plastic panel.
Unscrew the lower edge of the glove box.
Open the glovebox and undo the remaining screws along the top.
Pull the glovebox, disconnect the vent hose and the electrical connector.
Locate the stepping motor with a large "R" on it, unhook the wires and
unscrew the motor.
The passenger side arm is connected to a metal rod that operates additional
vents on the floor.
Unhook the rod and pull the stop arm off the shaft. Inspect for damage. My
arm was starting to develop a crack at the upper notch.
Remove the soft plastic rod bushing from the old arm and insert it into the
Installation is the reverse of removal. Once everything is done, start
the car and run the ACC calibration by pressing AUTO+OFF.