2004 Buick Century Owner's Manual - Page 261

Headlamp Aiming The vehicle has a headlamp system equipped with horizontal and vertical aim indicators. The aim has been pre-set at the factory and should need no further adjustment. This is true even though the vertical and horizontal aim indicators may not fall exactly on the "0" (zero) marks on their scales. If the vehicle is damaged in an accident, the headlamp aim may be affected. Aim adjustment may be necessary if it is difficult to see lane markers, for horizontal aim, or if oncoming drivers flash their high beams at you, for vertical aim. If you believe the headlamps need to be re-aimed, we recommend that you take it to your dealer for service; however, it is possible for you to re-aim the headlamps as described in the following procedure. Notice: To make sure your headlamps are aimed properly, read all the instructions before beginning. Failure to follow these instructions could cause damage to headlamp parts. To check the aim, the vehicle should be properly prepared as follows: • The headlamps must be off for one hour prior to aiming and must remain off during this procedure. • The vehicle must have all four tires on a perfectly level surface. • If necessary, pads may be used on an uneven surface to help level the vehicle. • The vehicle should not have any snow, ice or mud attached to it. • The vehicle should be fully assembled and all other work stopped while headlamp aiming is being done. • There should not be any cargo or loading of the vehicle. It should however, have a full fuel tank and one person or 160 lbs (75 kg) on the driver's seat. • Close all doors. • Tires should be properly inflated. • Rock the vehicle to stabilize the suspension. 5-49