My z110bt is permently in ATT and I cant change the volume or get it off ATT. I couldnt pull the pin out, So I took some extra VSS wire and filled the pin location that the by pass is moved to instead of the mute wire. I grounded that and the Brake lead to a bolt on the left side under my AC control box and the black ground to the right side.
below
http://www.350z-tech.com/w/images/f/fa/DVD009.jpgAlso in doing the install some how I caused the gauges to not work beside the back lights. And doing some research I have found that the AC unit is directly connected to the gauges. The only thing that involves the AC controls is the VSS wire splice. I dont know what happen I am hoping its something simple like a connector is not connected. VBLUE got anything? THANKS