Cadillac 2006 DTS Owner's Manual page 346

7. Locate the vertical headlamp aiming screws. They
are located under the hood near each headlamp
assembly. First lift the flap to access either of them.
Each one is the top outboard screw by the " V"
on the cover panel next to the aiming flap.
The adjustment screw can be turned with a 6 mm
hex wrench.
5-46
8. Turn the vertical aiming screw until the headlamp
beam is aimed to the horizontal tape line. If you
turn it clockwise, it will raise the beam and if
you turn it counterclockwise, it will lower the beam.
The top edge of the cut-off should be positioned
at the bottom edge of the horizontal tape line.
9. Repeat Steps 7 and 8 for the opposite headlamp.