Im new to this forum and have almost no experience with cars so I have been struggling on where to find info on how to repair my problem. I am handy enough to handle the work, i just dont have the knowledge or experience(i know those 2 are pretty important)

Car: 97 Chevy Blazer 4x4 4DR

Problem: Radio gives static noise the goes up and down with engine RPM. Radio comes in clear when engine is off.

What I think I know: Through some searching and reading I'm almost certain it is "alternator whine."

The issue I have is that i dont know where to begin to try and fix this problem. I know nothing about how the system is wired. I bought the car with a kenwood HU installed. There is no sub.

If anyone has any suggestions or could point me to a place with information about this problem would be great.

 

Also forgot to mention that this problem started to occur after the electrical ignition switch needed to be replaced. This was diagnosed and fixed by a garage and I didn't do any of the work myself. Is there somewhere they could have missed a ground or wired wrong?