I found something pretty interesting while messing around with my system the other night (i've noticed it before, but never really focused on it).

Now I have engine noise going through my system, but the is the kicker;

1) The engine noise is only when I have the HID's on (which are pretty much most of the time), now when I turn them off the noise pretty much either disappears, or is completely inaudible to my hearing.

2) Now observing the same thing above, if the engine is off (sett to ACC or whatever the hell it is called when power is still being provided, but the engine is off). I don't hear the noise at all (HID's are still on).

I'm pretty much living with it, but it was an interesting observation. Does anyone have any clues what the issue might be? I don't think it's ground, but who knows.

 

I'm pretty sure it's your alternator. The HID's draw a lot of current which makes the alternator work harder, hence the noise. Lots of people with noise problems lately... sticky time?