Plarsson - I have a Pioneer head unit, JL 6"X9" in the rear hooked up to a Pioneer Amp, I have checked the speakers and there is definately no short, if it does short aginst the body it shorts the speaker hence no sound out of that speaker. The sound is there wether it is on radio or CD, it doesn't seem to be relavant to the amps as no matter the volume the noise satys the same volume (eg very dim, can only hear it when Volume is set to 0/ CD is paused). It is definatley engine noise, ie you hear electronic noise as the engine revs and the brake switch cause a staticy click in the speakers.
Also I forgot to mention I have an intermittant problem (happened twice now) where I have started the car at night and then turned the headlights on and the Parkers/dashlights fuse will blow, then as soon as I use the indicators they will blink sowly/dimmly for 3 clicks and then the indicators fuse will blow.
Don't know iof this has anything to do with it or they are isolated problems.
Give me any bolt and I will snap the head off.(ezyouts.... greatest invention ever)