Buick 2001 LeSabre Owner's Manual page 308

4. Turn on the low beam headlamps and place a piece of
cardboard or equivalent in front of the headlamp not
being aimed. This should allow the beam cut
headlamp being aimed to be seen on the flat surface.
NOTICE:
Do not cover a headlamp to improve beam
-
cut off when aiming. Covering a headlamp may
cause excessive heat build
damage to the headlamp.
6-38
-
off of the
-
up which may cause
5. Turn the vertical aiming screw (C) until the
headlamp beam is aimed to the horizontal tape line.