I've had my E320 for about a year and the 2 dash speakers don't work. I toned the wires back to the 25 pin plug in the rear trunk. Why do these run back here vs. going to the head unit or an amp? Am I missing an amp? If so, does anyone know what model? I thought the rear plug was for a CD Changer and not an amp. There is an antenna cable and motorized antenna wire that aren't connected as well as a phoenix clip that looks to run back to the head unit. Any help would be appreciated, the door speakers are mid to low range and the sound currently sucks.