headlight levelling

I have a 2003 Civic 1.6 SE Sport (Europe/UK). I've noticed that when I
use the headlight levelling thumbwheel, I can't see anything happening
with the headlights. I'd at least expect to see the beam moving up and
down.

How does the headlight leveling work ?

Where should I look to figure out what the problem is (if there is one) ?

 

Best place to do it would be about 15 or more feet away from a wall so
you can see the light beam.

 

That's what I've been doing. When I move the thumbwheel, nothing happens
to the beam.

 

....so, counselor-- you would conclude therefore that the adjuster is broken,
yes? Repair or replace, eh what?

 

I kind of figured that.

I figured that too. Obviously you are far too busy being clever to have
noticed what my original questions were:

- how does it actually work ?

- and where do I look to try to diagnose the problem ?