Is my alternator going out?

[df2x4]

The whining through the stereo speakers can be noise from failed diode(s) in the alternator, but can also be a poor ground in the stereo wiring - especially if it's got an aftermarket unit, depending on how it's wired in, and whether or not there's aftermarket amplifiers in the mix.

Richard

One of my dad's earlier 400s did this straight from the factory when it was new. Very slight alternator whine through the stereo when it was powered on. Seemed to be most noticeable when playing a cassette IIRC. He had it fixed under warranty but unfortunately I don't remember what the cause was... I'd bet on a ground issue though.