I have a 2008 chevy cobalt. I recently bought a new aftermarket radio for my car. By the next day, my cars battery was dead. After I checked it out, I noticed the amp does not turn off with the car. When I turn off the car, the amp light turns off. But the sub makes a small pop noise and the amp light turns on by itself. The amp remote wire is wired with the radios amp turn on wire. Any advice?