Graphic is only an example. There may be differences in specific details depending on engine version.
Unscrew all bolts.
Remove underbody panelling (1).
Installation note: Make sure underbody panelling (1) is correctly seated.
BMW X3 Owners Manual > Mirrors: Exterior mirrors
General information
The mirror on the passenger side is more
curved than the driver's side mirror.
Depending on the vehicle equipment, the mirror
setting is stored for the profile currently in
use. When the vehicle is unlocked via the remote
control, the position is automatically retrieved
...