Okay, so I looked further into the electricals of the trunk of my car and noticed a blue and black wire running from front to back.

YES!
However...

The previous owner of my car hooked up a brake/reverse/turn signal system for hauling trailers so the two wires I found led to this massive plug along with these other ones that came from the rear car lights.

So I took apart the plug to isolate the two wires running from the front
and hooked up my multimeter like a good person should :)

When the key was in position I of the ignition (accessory), I'd get
nothing, and at II I'd get 11.38v, YES!
And when I put the light switch to a position in between OFF and daytime running
lights so that all the lights would be off, I still got a steady 11.38 volts.

Here's my problem... whenever I hit the brakes I hear a hum or beep from my car speakers. The reason I say hum or beep is because when I adjust a slider on
the box going to the trailer light plug, it goes from bip bip bip bip bip to a steady beeeeeeeeeeeeeeep. These noises aren't loud at all, but I do notice them
whenever I hit the brakes.

The CD changer works just fine and so does the radio, is this problem just a hindrance or should I be worried about it?