mystery purple wire

I recently bought a used 2000 Pontiac with a non-working OEM stereo.  After checking fuses, I removed the unit to find out that the previous owner had cut the wiring harness hooking into the deck.  I rebuilt the harness, connected it, but no luck.  I can get the button backlights to turn on (with the headlight controls), and I've checked the 12V line all seem fine. 

So I checked the wiring diagrams to help in trouble shooting ( https://www.the12volt.com/installbay/detail.asp?info=alarm&year=2000&make=Pontiac&model=Sunfire&ID=18812&type=Stereo)  and it seems I have a mystery purple wire, and also no ACC (yellow) wire.  I'm not sure what this purple wire is supposed to do, but it stays at 0V regardless of the ignition position.  Has anyone seen a 2000 Pontiac Sunfire where they have switched the yellow ACC wire to a purple wire?  Any clues what this might be?

With aftermarket stuff, purple is often ground. It seems to be the case here. As for a switched power wire, you may need to run one yourself.

it could be either of these based on the pin location of the wire...

the first box is the pin location on the harness.......if it's just a basic radio then likely it's the class II wire....this generation of radios do not have an Acc circuit but are clocked on & off via data....

damn kgerry,

everytime i think im gonna have to post some advice or a tip, i get to the bottom of the thread to see that youve summed it all up. you are correct, no switched acc circuit @ the factory deck, class II databus.

that said, if i could just get you bastards to stop talking canadian dollar figures instead of US I'd have nothing but pleasant things to say

kudos

Thanks for the tip kgerry!  I found this website based on your post:  http://members.shaw.ca/johnz24/howto/2kaudio.html  It outlines the class 2 wiring system and some pointers on running a switched 12V yourself.  Luckily this car doesn't have power windows, so there's one fuse location left unpopulated with a ACC switched 12V line.