How to Adjust Headlights on a Mercury Grand Marquisby Alibaster Smith
Proper headlight adjustment is essential for safe night driving. If your Grand Marquis' headlights are out of alignment, you will notice a dramatic reduction in nighttime visibility. This, in turn, can create potentially dangerous situations on public roads. On a Grand Marquis, there are just two adjustment screws. The vertical screw adjusts the headlight up and down, while the horizontal screw adjusts the headlight left and right.
Pull the hood release lever and open the hood. It may be helpful to park the car in a garage or somewhere where you are able to shine the headlights against a flat surface.
Mark the horizontal and vertical center lines of the headlights on the wall. To do this, find the center of your headlights. Then place a strip of masking tape horizontally on the wall that corresponds to the center of your vehicle's headlights (you can use just one section of masking tape for this). Do the same for the vertical center line, except that you will place the masking tape vertically instead of horizontally (there will be two sections of masking tape this time).
Turn on the headlights. Make sure that the headlights are shining on a wall or other flat surface and that the vehicle is approximately 10 to 25 feet away from the wall.
Locate the headlights. Starting with the driver's side headlight, locate the adjustment screws. They will be located on the top and front of the headlight. The horizontal screw will adjust the headlight from side to side. The vertical screw will adjust the headlight up and down.
Adjust the horizontal and vertical adjustment screws so that your low beam headlight is 2 to 4 inches below the horizontal center line and 2 to 4 inches to the right of the vertical center line.
Remove the masking tape from the wall and close the hood.