The noise is alternator whine and you likely have a lose ground wire (black wire) behind the radio/nav system I have the steering wheel. I did search and found the c6 audio faq and related threads on what is needed for a head unit install, but.
Chevy Corvette Whining Sound: Identification + How to Fix | Drivetrain
Diagnose and eliminate the root causes of alternator whine
Master the electrical system fixes needed for silent, clear.
The best advice the owner had to give was that years ago he did an install on a corvette and it had the same alternator. The most common concern for vehicle owners is alternator whine that transmits through the audio system speakers. Learn what alternator whining noise usually means, what to check first, likely fixes, and when it needs fast repair. In this video, we dive deep into the causes of alternator whine, including grounding issues, poorly shielded cables,.
If noise goes away you have several choices, alternator, power steering pump (unlikely) idler pulley or tensioner pulley. For what it’s worth, there are 36 polls and if the engine is idling at 625 rpm and the alternator rotates at about 3 to 1.
