i got the annoying alternator whine after putting in the Pioneer D3, pulled the ground wire out of the harness and attached it to the bolt inside the dash but no help. I have a RSX with factory bose amp (no rca cables) & sub. Also when i unplugged the preamp rca cables, the noise disappeared. I want to try moving the ground to a different spot but not sure where?

 

Try directly to the neg terminal on the battery.

Or a good chassis ground, not a secondary ground to metal in the dash.

 

Yep, I wouldn't even use the metal pillars that bolt to the chassis and hold the dash up. Just drill a hole in the nearest part of the chassis itself, run a wire down to there with a ring terminal on it, screw it down and you're good.

 

What are you using as an interface between the Pioneer HU and the Bose system? 94

 

i would look as mentioned before at the cables that connect to the bose unit.. likely pinched or run near a source of noise...