So i have an aftermarket stereo and aftermarket speakers in the car, and all but one of the speakers in the back are playing. Even the other speaker in the back goes on and off sometimes. When you look at the wiring at the receiver, if you play around with it, like literally just moving it over or something it effects all the speakers in the car. I took apart part of the back seat and it looks like the previous owner made some splices and just used wire nuts and tape to finish the job. Could that be why the speakers aren't working correctly? There is also a black wire that is connected to the wiring harness up by the receiver but its not connected to anything. Maybe its supposed to be a ground? any and all help is greatly appreciated.