XM Power Wires? ('05 with XM stereo integrated (add-on))

I have an '05 with Nav and the ultimate lockpick with a DVD and an integrated XM unit from the Cleveland dealer ("Eddie"). Everything works great.

After installing the DVD player, I noticed the the XM sound volume was lower (at the same volume number). I installe a power on/off switch for the DVD power because, even when the DVD unit is powered off it "takes away" from the volume on the XM --shares speaker wire input??? When I listen to XM, I cut the power to the DVD player. This make the XM about 25% louder.

I'd like to also be able to switch off the power going to the XM radio when I run the DVD player - to enhance it's sound. In order to do this, I need to know which wire in the cable running back to the XM radio carries the power.

Anyone have a clue which one it is or how I can find out, other than trial and error?

Thanks in advance.

Rick :huh: