Headlight Wiring Woes

[Jean]

We will discuss THIS later.
it gets more complicated.
I only mention it since some mods have been made to your bike, and one mod we all like is to add louder and MORE horns. I thought you ought to be aware of this...2 horns will give the stock wiring a fit without a relay.
If you have the stock horn, you are probably OK for a while.
If you have the stock horn, you need to consider replacing it with some serious noise-makers.
Unlike loud pipes, LOUD horns DO save lives.

[hudson]

If you KNOW the actual LAMPS are good, the problem is probably an inadequate ground connecting the little (AND they ARE LITTLE!) sockets.
It is possible all 3 of the lamps are shot, though.
Did they work before the untimely end of your wiring harness inside the shell?

Yes. All bulbs worked before this happened. They have a green wire supplying power and are wired off of each other (like a daisy chain) and the wires from the main harness connect to each socket as well, according to the color codes. Since they are wired this way, wouldn't none of them be working due to inadequate ground or power?

I even switched out the socket and bulb on the neutral ind. wire with the oil pressure wires and it lit up!

If they DID, probably something got disconnected.
Normally, one lead comes off the common lead to the headlamp for the speedo lamps. The neutral lamp is fed from an independent "switched-power" lead since you want it to light in both day and night, but only when the switch is ON.
They all seem to share a ground, however, so that is what makes the ground the primary suspect.

I think it is something as simple as grounding, but if the other two bulbs tied to this lead have proper power and grounding to work, why wouldn't the neutral light?

Regarding the horn - the black wires from both the main harness and horn switch are together as shown in the schematic. I don't see the green & black lead coming from the main harness that connects to the horn itself (there are GR-BLK & a BLK wire that connect to horn). Where does it get its power?

BTW- Very funny about the smoke. Good way to break in a rookie!

[Jean]

Nasty thing about the stock wiring for the horn...the horn is HOT all the time...the switch just connects it to ground to make it sound.
This is logically contrary to how most things are wired, where the switch breaks the hot wire BEFORE it gets to the consumer (thing you want to work).
What this means to you is any short-circuit (scraped or faulty wire) up to and including the horn switch WILL burn or spark fearfully. It also means you can make a serious mess with the horn wires if you don't KNOW THIS.

The green/blk comes from some terminal that is hot when the switch is ON, and goes TO the horn. The black wire comes from the horn, to the switch*, and a brown wire grounds the other side of the switch to the common ground inside the headlight shell. NORMALLY.

Since your shell has been mocdified...I would check for the connection I mention with the [*]. The original set-up used a terminal on the switch "board" as a connection point. There ought to be a similar-function point on your terminal strip.
Another way to say this is, you (once again...OUGHT to) have 2 black wires in the shell that need to be joined to each other and no other wires.