I recently installed a new head unit (JVC Arsenal KD-AR3000) in my 99 CL 3.0, with the premium Bose sound system.

All that was replaced was the head unit, as I do not have the time/money right now to tackle a new amp and speakers. I bought the unit from Crutchfield, along with their wiring and mounting adapters. The install went flawlessly, and the unit fits perfectly snug, looks good, and sounds better than the factory headunit.

As I have read in some other posts here, I hear a faint, but some times noticable high-pitched whine that definitely rises and falls with engine RPMs. It seems a little worse when playing the radio versus playing CDs, but I think it is there all the time.

From what I've read in other similar posts, some common causes could be a grounding problem or possibly a problem with the factory amp. I guess my questions are, could I have a grounding problem even though ground wire from the headunit is connected to the ground wire on the Crutchfield adapter, which then connects the the vehicle's wiring harness? If so, what could I possibly do to resolve that?

If it may be the factory amp, is there anything I could do short of replacing it? Trust me, I'd like to replace it, but that's just not going to happen right now.

This isn't a horrible problem, and most of the time I don't notice it, but if there is something fairly basic I could do to solve it, that would be great.