You can remove the wheel and go though the little door in the splash shield with a 10 mm on a long extension, or access the outside one through the marker lamp hole and the inside one by feel from the back of the headlight.
It helps to remove the top bolt in the bumper cover by the headlight and lift the cover a bit to persuade the unit out.

I usually remove the lower screw-in adjusters on the unit to provide a bit more clearance, but some say this is not necessary.