Gurus, I got another one for you.

What is the deal with the black and brown wires on the 91 diagram (and in real life) that go to the auxillary headlight thing? There is no extra headlight, so what do these two wires do? Right now, they're not connected to anything, and I don't know what they were connected to before I started my rebuild. Any thoughts?

Side light.  Schematic here:

http://www.scribd.com/doc/7178815/Suzuki-GS500-Full-Service-Manual

Unused on my bike too.

Okay, so I don't need to plug those into anything to complete a circuit then?

Also, any idea about the mystery orange wire? It doesn't seem to go to connect to anything. It comes into the wiring connector that the left switch cluster connects to.

I know there are some unused wires on the North American bikes that are for extra lights in other markets.

Yeah, those wires are just extra.  One is Hot with key On, other is just a ground.  I utilized them two power a relay when hooking up my Angel Eyes.

Yes, the orange wire is hot with the key on.  It is the wire that supplies power to your ignition and several other things.  You could wire something to it if you wanted it to be on whenever they key is on.

lol, hmmm.... like my headlight? 

So it seems those three wires, the orange, black, and brown, are not used for anything (typically) and just need to be out of the way and safe. Guess I'll now start hunting down why the hell my headlight doesn't work. Thanks for the replies, guys, I really appreciate it. 

Black/white + Brown  - those are sidelights on euro bikes for them there's a switch for lights with 3 positions:

off->parking->on ,in parking a little 4W bulb lights up in the headlight with rears ,the same happens when you lock

the steering and turn the key one click to the left, the lights stay on with no key in switch .

Good idea to use those "extra" wires for some LEDs maybe