If you mean in ZM3, than I'm not sure how to do that, but I'll cover what I know about headlights here, just in case it's useful.
There are global headlight beam aim settings in 'visualsettings.dat' in this section of the file:car.headlights.angle 0.03 car.headlights.split 0.0 car.headlights.global.HeadlightIntensityMult 1.5 car.headlights.global.HeadlightDistMult 0.9 car.headlights.global.ConeInnerAngleMod 0.4 car.headlights.global.ConeOuterAngleMod 0.37 car.headlights.global.OnlyOneLightMod 1.0 car.headlights.global.Fake2LightsAngleMod 0.94 car.headlights.global.Fake2LightsDisplacementMod 0.17 car.headlights.submarine.Fake2LightsAngleMod 0.830 car.headlights.submarine.Fake2LightsDisplacementMod 0.0 car.headlights.fullbeam.IntensityMult 1.0 car.headlights.fullbeam.DistMult 1.5 car.headlights.fullbeam.CoronaIntensityMult 2.0 car.headlights.fullbeam.CoronaSizeMult 2.0 car.headlights.aim.fullbeam.mod -0.10 car.headlights.aim.dippedbeam.mod -0.11 car.headlights.aim.fullbeam.angle -0.15 car.headlights.aim.dipeedbeam.angle 0.7 car.headlights.player.intensitymult 3.6 car.headlights.player.distmult 8.0 car.headlights.player.exponentmult 4.0
They are pretty self-explainatory. Play about with the values to see what they do exactly. Been years since I edited them, can't quite remember the exact details (also, yeah, that's how Rockstar spells 'dipped' sometimes ('car.headlights.aim.dipeedbeam.angle' etc)).
You can control what headlight beam texture (in 'graphics.ytd') the vehicle uses by editing this section in the vehicles carcols (in the '<Lights>' section for that car)<headLight> <intensity value="1.00000000"/> <falloffMax value="35.00000000"/> <falloffExponent value="16.00000000"/> <innerConeAngle value="0.00000000"/> <outerConeAngle value="60.21000000"/> <emmissiveBoost value="false"/> <color value="0xFFFFFFCC"/> <textureName>vehiclelight_car_standard70s</textureName> <!-- this is the name of the 'graphics.ytd' texture here --> <mirrorTexture value="false"/> </headLight>
Use the vehicle's carvariations to figure out what lightSettings value the vehicle uses:
Carvariations:<lightSettings value="18" />
Carcols:<id value="18"/> <!-- in the '<Lights>' section of carcols -->
You can edit/duplicate/create your own headlight beam textures in 'graphics.ytd', as many as you want, the name can be anything you like, just use the same name in carcols obvs.
If you position the texture further to the left, the headlight beams will shine higher in game:
Headlight Beam Texture Stretched Further to Left (Shines Higher In-Game):
Unlike 'vehshare.ytd' textures, the 'graphics.ytd' cannot be placed in a vehicle's '.ytd' to get it to use those over the ones in 'graphics.ytd'. So whatever headlight textures you use, you'll have to place them in 'graphics.ytd'.
That pretty much covers it, should be of some use anyway.