I guess I do need a bit more info. I am trying to find a cross from the Onstar connectors on the DeVille to the connector on my 98 Seville. So far, I am going to assume the 'ppl' data wire would be the same. I won't need to worry about the LED wires, as there is no led. MIC will be connected to the moto unit along with the keypad. I guess the only wires I need to worry about are the MUTE, Audio +/- to amp, GROUND, Fused Battery, and Ignition Sense. I am assuming you are using the orange wire for your 12+ constant. What wire on your DTS are you using for radio mute?
Here is the cross reference I am getting from following the schematics:
SLS_bt_mod_wir.png
Please tell me what you think. I hope this will work.