How do you adjust the headlights on a 2002 Mazda Miata?

Not much on that job. Usually when you buy a new headlight unit they come complete, you just bolt them in.

https://www.google.com/search?q=2002+Chrysler+Sebring+headlight+adjustment+screws

and

https://www.google.com/search?q=2002+Chrysler+Sebring+replace+headlight+assembly

..

The headlight adjustment screws on a 2003 Mazda Tribute are located on the back of the headlight assembly.

Are your headlights beams too high? too low? Then bear with me and maybe I can help
Horizontal headlight adjustment is easy. See the screw on the inside top of each light? turn the screw left and your headlight beam goes outward; turn the screw right and the beam goes inward, (toward the center.)
Okay now Vertical adjustment is a little more involved. Start by removing the corner lens; take out the screw on top of the headlight and pull the corner lens forward. This will allow you to access two 10mm bolts holding the headlights in on the sides.
Remove those, along with one 10mm nut on the backside of the headlight assembly (near where your bulbs plug in). Remove your headlight bulbs carefully - I usually put a paper towel around them to protect them from dirt and oil. Now the only thing holding your light housings on are the horizontal adjustment
screws. Just slide the screws out from the lens, and then remove the headlight from the car.
If you look at your headlights now, there is another screw that looks just like the horizontal adjustment screw.
In order to adjust this, you need to remove the 10mm bolt labeled "A".
Now slide the plastic headlight base off of that bolt. The whole plastic base will now be free to swivel on the adjustment screw. What you need to do now is to turn the plastic base around the screw; if you turn it clockwise or right, it will lower your headlight beam when reinstalled. If you turn it left, it will raise the beams.
I ended up only turning each side lower by one revolution. You shouldn't need more than one or two turns. It also becomes hard to slide the housing back over the "A" bolt after two turns. If
in doubt about whether the beams will be raised or lowered, on the final pic you can see the clean area of the bolt on the left side. if you lengthen this side, it causes the beam to go down.
Its really easier to understand as you are doing it, if this does not seem clear. Just use some common sense and you'll see what I mean.
Installation is the reverse of removal.

Is there power to the connector?

Turn on your headlights and locate the two adjustment holes that have the adjustment screws inside them on the sides of each headlight. The top hole has the vertical adjustment screw and the bottom hole has the horizontal adjustment screw. Turn the vertical screw clockwise to raise the beam and counterclockwise to lower; turn the horizontal screw clockwise to move the beam right and counterclockwise to move the beam left.

click this link for more help:--- http://technoanswers.blogspot.com/2011/05/how-to-adjust-headlight-beam-on.html --------- This should help.thanks.Helpmech.

• Always adjust lights with optical headlight aimer VAS 5107, using detailed aiming procedure and specifications
• Low and high beams are adjusted simultaneously.

Left headlight (adjustment screws for right headlight are mirror image):
1 - Lateral adjustment 2 - Height adjustment

• Access adjustment screws through hole in lock carrier (Phillips head or socket head).
• Turn the adjusting screws for lateral adjustment -1- and height adjustment -2- until the correct setting is achieved.

NOTE: Where equipped, ensure equal movement/function of headlights during automatic headlight range adjustment.

At the back of the headlight there are screws that adjust up and down and left to right,look carefully as it will be written on the headlight,you will see it stamped into the top of the housing just follow the indicators on the light to adjust it down,and park in front of a wall on a flat surface if possible at night or dusk to see how much youve changed the height,its not difficult to do just look carefully

two screws on each headlight control the direction the headlights are aimed. One screw, usually at the top but sometimes below the headlight, adjusts the headlight up and down. The other screw, located to one side, controls the headlight from right to left. Turning the appropriate screw one direction or the other will change the direction the headlight points.
In order to aim your headlights you need to have a flat vertical surface you can aim your headlights at in front of a level surface on which to park the car. If your driveway is level your garage door is the perfect place to aim your headlights.
The tools you will need for this job are simple. Masking tape is used to mark where the headlights are to be aimed and a screwdriver is needed to adjust the headlights. A tape measure will be necessary to measure the distance of the vehicle to the surface you're using to check the aim and to measure the up and down distances from your marks

The adjustment screws/nuts should be located either on the top of the headlamp assembly, behind the headlamp assembly, or near the frame rail by the radiator support.

You will have vertical adjustment screws for each independent beam (separate highs and separate lows, but will be same screw if highs and lows are the same bulb). You may also have additional horizontal adjustment screws as well

Park your car on a level ground 30 feet from a wall and measure the height from the ground to the bulb and mark on a wall (do this for highs beams and low beams if the bulbs are separate, if highs and lows are the same bulb, only do it for the lows)

If the headlights read VOR, then aim the brightest part or cutoff part just below the mark on the wall. If it says VOL or nothing, aim them 2 inches below the mark on the wall.

There should be an access panel at the back of the headlight assembly. Remove the cover and replace the halogen bulb. Pretty easy job. Some of the covers screw off.