Starter/Battery issue

[Parish]

Alright I know this is a terrible mistake however i replaced my starter yesterday. Took the battery out and everything. No problems with the starter there were five wires connected to my battery however before now I have six that look like they should be on the battery terminals. I dont know where this extra connector came from. I wan't to find out what its for and where it goes but i dont know where to begin if anyone could help me figure this out that would be awesome. I have pictures if it would help anyone lemme know. Thanks in advance.
BTW my car is a 1990 Talon TSI AWD

 

[Livid]

Post some pics, or just try tracing the wire.

 

[Parish]

The extra wire I found goes into the firewall on the driver side I'll go take a few pics now

 

[Parish]

photobucket is currently down, lemme look for something else

 

[Parish]

alright here is the wire

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and here is where it goes, i couldnt get a great angle on the shot, it runs along the firewall to the driver side

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i can take other pictures pretty quick so if there are any requests lemme know

 

[Livid]

Almost looks like the same gauge as an amp would be. Do you have a sound system in your car or have you ever? I would try pulling up the carpet where your toes would be on the passenger side and see if you see the wire coming out through the engine bay, if it was a aftermarket wire it would most likely come through at that point. If not, then I might have to let my Gen1 friends take over on this one.

 

[Parish]

I wouldnt doubt it, theres a nice alpine head unit in it when i bought it and lot of extra wires under the dash. I don't know where it was hooked up before i took the battery off so i'm not sure where to connect it now.

 

[Parish]

Alright earlier today i found the right location for the wires using the five that were connected and the other one i tied up in electical tape. It worked fine, I got into the car and turned on the radio and stuff. later I hooked it back up the same way just now and i get smoke, so i unhooked it in a hurry, but what the hell? Any ideas?

 

[Livid]

When you hook it in where do u get smoke? From the wire? Also, if it is smoking it means there's most likely no fuse hooked up to that wire so I would be careful. Sounds like it could be someone had an amp at one point, removed it, and never took out the wire so its shorting out on bare metal somewhere.