Ok, here's the deal. My horn, suprisingly enough does not work. If I run a wire from the horn itself to the positive terminal, it works. If I run a wire from the wheel hub (not sure if that's what it's called, the thing circled in green) to one of the little brass plates (circled in red) that also touches the big black plate (with the yellow X on it) the horn goes off. So, as far as I can tell, the only problem here is between the horn button and these three compenents. What I can't figure out is, how to get all the parts in the 2nd picture to somehow contact said three points when I press the horn button. So, here are my questions.

1. Where does the wire from the horn button go, and is it too short to go there?

2. I assume the spring/rod/black plastic piece combo go in the green cylinder (circled in purple). What function do they serve?

3. Am I missing any pieces?

Yes, I do have the rest of the steering wheel. I hope this is clear, and will maybe help out other folks with similar problems. Thanks in advance!

EDIT: I should probably include the pictures...

 

I continue to amaze myself. I'm partially wrong in what I've said previously, the steering wheel "hub" has absolutely nothing to do with the circuit for the horn. So totally disregard that.