On my 1990 Mazda 121, the low beam (and sometimes high beam) lights fail due to a faulty light switch on the steering wheel console. I have to pull it apart and clean up the contacts about once every year when it does it. The tail lights also go out. I can tell it has failed again as the dashboard lighting goes out. Andrew.
There is an adjustment screw in the top or side of the headlight nacelle. Turn it one way and it raises or lowers the beam and the other one moves it sideways.
headlight switch is probaly your trouble
The 1999 Chevrolet has a separate fuse for the low beam headlights. The low beam headlight fuse, can be found in the fuse box.
High beam headlights reveal objects at a distance of at least 450 feet away. High beam headlights allow the driver to view obstacles in the road much sooner than low beam headlights.
Use your high-beam headlights at night whenever it is legal and safe.
You use low beam headlights when you're in a town or city in any location.
On most vehicles, the low beam headlights are the outside pair of lights. This is true when the headlights are side by side. When the two sets of lights are stacked, the low beam headlights are usually on the bottom.
Car headlights have to be able to "dip" so as not to dazzle oncoming traffic, they therefore can switch between a "high" beam and a "dipped" beam and thus have a dual beam.
Use your high-beam headlights at night whenever it is legal and safe.
The headlight fixture probably contains moisture on the inside. When the headlights are "on", the moisture clouds the light beam, diffusing the light.
Low beam headlight should illuminate 85 feet of the roadway. Newer low beam headlights illuminate more of the road than older headlights.
I was looking at the 1996 Mercury Grand Marquis Owner Guide and it shows that you can change each of the ( 4 light bulbs for the 2 low beam and the 2 high beam headlights ) ( the low beam headlights take bulb # 9006 ) ( the high beam headlights take bulb # 9005 )