Possible bad ground,look into a ground loop isolator.Originally Posted by Wakeboy1337
I had an aftermarket JVC headunit in my car for a few months with no problems and then I decided to switch over to a much nicer DUAL headunit. When my engine i running I can hear the high pitch squeal in the speakers and it's driving me insane. I'm running stock speakers and the factory bose amp is still wired in. I can hear the squeal on any input mode as long as the motor is running. Anyone have an idea?
Yes the Dual brand car radios are a hit or miss headunit,a friend of mine has killed 4 of them all different models.
