9 Guage to 10 gauge Brown to igntion switch?

[Fiat88]

While I have the consoles out to replace my heater core, fan, and valve I'm trying to inspect and clean up any wiring which is cut, spliced, or have oxidized crimps for safety and for good connections. Overall the wiring looks good just a few PO wire splices I found. While I was under there, I saw a brown wire under the dash which had black tape on it in one spot. Looked like its going to the ignition switch, its around 10 gauge and it connects to a little larger wire around 9 guage. Looked like it had the original factory male and female quick disconnect terminals, so I tried cleaning them with contact electrical cleaner and I guess I played with it too much and the female or male terminal broke off the 9 guage wire. I can't seem to find a replacement terminal big enough to accept the wire strands. Should I just solder the wires together? Hopefully someone will know what wire I'm referring to. BTW, It's a '79 with an Automatic trans. Thanks.

[wikkid]

Um, be sure the brown wire actually goes to the ignition switch, as the brown wire carries the power to the switch that then runs all the other circuits. If it's that one, there normally wouldn't be a splice or connector, as it comes from the battery lead. The wiring diagram for your car here should help.

[Fiat88]

I'll have to double check. Also its an Automatic trans.

[Fiat88]

The brown wire is coming from the ignition switch.

[wikkid]

It's actually going to the ignition switch, at least in stock configuration. It is the main 12V power feed to the switch from the battery, and the switch connects it to other wires that go out and run the other stuff on the car (highly technical description there!)
The white wire should be traceable, then, back to the conncetion point to the main 12V battery cable that comes from the trunk up into the engine compartment. Why it would be white? No idea. It's really helpful to work with good wiring diagrams, like the ones available here.