I drove my new Bonneville in the dark for the first time, and the driver'* side headlight was pointing skyward by a mile. OK, maybe a few feet. Well, when parked about 8 feet in front of the garage door the left side was 4 inches higher than the right. And that was enough to really light up the inside of that poor van in front of me.
The adjuster is a torx head screw that turns pretty easy. Chances are pretty good that your average car owner will not have the correct Torx socket. You could use a pair of pliers (please don't!). But a regular 7mm (6point) socket worked very well for me.
And here'* a picture for those who are looking for the adjuster.