you need to aim your headlights. On the 99-04 Mustangs there is an adjuster on the headlight assmebly. you'll need an Allan key to adjust the light. park your car with the front a few inches from the a wall and mark the center of your beams with a marker on the wall. back up 25 feet and lower both headlights until they about 4 inches below the marks you have made.