radio engine noise

[openroad]

I am trying to use a satellite radio unit in my 2003 Z4. I am picking up engine noise through the cigarette lighter jack. The radio aux jack works fine with an I pod that is not using car power

 

[NeilP]

I've had the same issue when running to the factory aux.

You may find that running a dedicated feed separately will cure the issue (due to the ground loop) or failing that a ground loop isolator would fix the issue (you would just have to hide it away.

Though I never bothered to fix this issue in mine as I planned to upgrade the stereo to a separate system altogether.