Was digging around in my trunk preparing to wire up an aftermarket amp and found this connector under the spare tire. What does this go to? I am guessing it's for the factory subwoofer that my car doesn't have? If it is, can I splice into it for signal to my amp? Thanks for the help!

 

There is a member here named Dennis Black who could "possibly" identify that.

Have you tried if you get a power on that connector plug when you turn the radio on with a multi-tester or an old school circuit light tester?
I always use circuit test light to identify which power it goes through. It is simple to work with and works well for me. Good luck