For my non-monsoon non-onstar setup, I used a metra 97-2003 and couldn't find an ignition switched source, so I ran that wire on the metra harness to the switch I have for my gauges which are always on when the car is. If it makes any difference, my head unit is a Pioneer AVIC-D3.
I watched this guys videos a few times before making the decision to do it. http://youtu.be/jpYtPSkVbyI
Use that information at your own risk.
The right way to do it is buying a wiring harness that MSRP is around $120. You can generally find them for around $60 if you search.
Originally Posted by W-Body Store
