2003 Cadillac DeVille Owner's Manual - Page 321

Headlamp aiming is done with the vehicle low-beam lamps. The high-beam lamps will be correctly aimed if the low-beam lamps are aimed properly. The headlamp aiming devices are under the hood near the headlamps. Headlamp Horizontal Aiming Turn the horizontal aiming screw (A) until the indicator (B) is lined up with zero. If you believe your headlamps need horizontal (IeWright) adjustment, follow the horizontal aiming procedure. If you believe your headlamps need only vertical (up/down) adjustment, follow only the vertical aiming procedure. Once the horizontal aim is adjusted, then adjust the vertical aim. Headlamp Vertical Aiming Nofice: Horizontal aiming must be performed before making any adjustments to the vertical aim. Adjusting the vertical aim first will result in an incorrect headlamp aim. Adjustment screws can be turned with an E8 Torn@ socket or T15 Torx@ screwdriver. 5-50