Help please 2001 Grand Am stereo wiring

I am trying to put an aftermarket stereo in my son's 2001 grand am. The stock stereo harness has been cut. I bought the Factory 2001 Grand Am Harness Metra 71-2003-1 & a Class II Data Bus interface adapter - GMOS-01 from Metra online. I have the GMOS-1 all wired up and ready to go how ever the Metra 71-2003-1 wire coloring does not match. That is not the real problem. I found the schematic as to what wires go to where except the 2 purple wires. Here is the schematic. http://ww2.justanswer.com/uploads/GUYVANIDERSTINE/2010-06-28_102526_B.gif The first purple wire is in spot A1 on schematic and says it is "Class 2 Serial Data" the second purple wire is in spot B6 and says it is "Gain Control Signal" How do I figure out which is which and what happens if they get hooked up backwards?

idk if you got this taken care of but here are some better wire diagrams with color pics :thumbsup:

http://www.bulldogsecurity.com/diagrams/

And Welcome to AF!