If the changer audio input is open or terminated with the iso-max I get popping and buzzing from the bi-X headlights but no alternator whine. If I terminate the changer input with the ice>link I get alternator whine but no popping or headlight hiss. Moving the ice>link cable does not change anything. From this I conclude the following:

1) The radio to changer link is picking up the popping noise and hiss. I believe this is due to the fact the the far-end is not grounded is the point where the cable shielding is grounded, anything that floats the ground causes a problem. Now that I type this I'm not sure if I tried just grounding the changer side of the iso-max.
2) The alternator noise is coming in on the ice>link power and ground. May only be when it is connected to the changer input.

I was thinking that possibly filtering the ICE>link DC may help. Is the power clean or noisy in the X5? I don't have access to a scope these days. I have not had to use a choke on a car audio project in a long time. Is it just that the ICE>link does little or no filtering and most audio equipment does these days? I'm still hoping that the noise is ground loop related since the path from the radio to the rear to the ice>link is so long.

I think my next step is to try a radio-end kit to shorten the total run length. It will need a little re-wire since I have bluetooth, but it is the only thing I can think of at this point.


At this point I think I'm going to try the radio end kit.