Alternator Whine

[TexaSC]

I have an alternator whine that only comes through the stereo and I have done just about everything to try to find the problem... car has two, 1foot long four gauge grounds to bare metal, tested resistance by voltmeter... tried noise filter and ground loop isolators on head unit, still there.. the alternator itself doesnt make any noise and charges fine and ive tested it.. last thing I can think of is an expensive high current alternator filter, any one been down this road before??

 

[Peewee]

9 times out of 10 stereo whine is caused by a bad earth.

Check the battery to body earth, the battery to block earth, block to body, ecu to body, and lastly, cd to body.

If you have an aftermarket amp, check the earths on that too, and make sure the power wire doesn't come close to the signal wires.