I have a 2002 Buick Century that I just bought. It had an aftermarket stereo installed, but we changed it out for a better model because the faceplate was gone. When I installed the new stereo, there was a Pre-amp output with an Amplifier switch cable already running out from under the dash into the floor board. My question is, how do I find out where it is running to? I looked in the trunk and didn't find anything. I just got a sub and if i can use the wiring that's already there, it would make my life a lot easier. I assume that the pre-amp output was originally running to an amplifier that has since been removed, but on my particular stereo (a Sony CDX-GT410U) the output can be changed to a sub out.
I think this cable is running to nothing. I think it used to be connected to an amp that was removed when the previous owner sold the car. It may be going to a speaker, but I don't think so.