Recently my '97 f-150 has started making a loud whistle through the speaker that intensifies or calms down with the rpm's I've noticed. And sometimes when driving at night switch from bright lights to dim will cause the radio and certain electronics lose connection temporarily... I was thinking a lost ground somewhere? Has anyone had this problem and has figured it out or maybe have any kind of suggestion? The whistle sounds like a small super charger... would be pretty cool if it actually boosting the horsepower.