Hello, I have installed in my Ford Fiesta in the front doors two LS each with tweeter. My Autoradiio is a Pioneer DEH 5500. In addition is a subwoofer on board. I installed the power amplifier myself. That 6 years ago. I remember from my predecessor car that audio and power cables put together a beep when giving gas. In Fiesta I had no problem for 6 years now. Until the day before yesterday. Out of the blue the radio did not go any more. the boxes connected to the power stage. If I go to the gas or the electric window lifter, the sound will be higher. I have not changed anything to the cable or the configuration. What can the problem be?