2004 S40 Audio Hum
 

Hi All,

New to the forum. Owned a 1990 740 GLE and now I have a early 2004 S40. Love them both.

However, I don't love the stereo in the s40 and tried to replace it. I attached everything correctly (grounded the amp, etc..) but I'm still getting an engine hum that disappears at higher RPMs. For highway driving, fine, but for city driving it's annoying.

On hot days, the stereo will last for about half an hour on the highway and then buzz out of control.

Is this an issue with the factory amp? Does my car hate non-oem radios? Any advice would be appreciated.

Thank you.