Ford 1999 Taurus Owner's Manual page 263

Horizontal aim adjustment
1. Open the hood and lift the front end cover
from its velcro attachments. Locate the
horizontal level indicator and adjustment screw.
2. Use a 6mm socket and ratchet to turn the
horizontal adjusting screw until the horizontal
indicator is in line with the "0" reference.
258
Vertical aim adjustment
NOTE: The numbers shown on the vial indicate
beam direction in degrees up or down.
1. Locate the vertical level indicator and
adjustment screw.
2. Use a 6mm socket and ratchet to turn the
vertical adjustment screw until the bubble in
the horizontal level indicator is centered in the
vial.
3. Replace the sight shield and close the hood.