Ok, so I own a 2009 Cobalt LT without OnStar, and I'm attempting to wire up an interface for a replacement radio, but everywhere I've looked I've seen the same one recommended which does not fit the OEM harness, which I now know first hand having bought the $70 part and tried to install it. The part in question is the PAC C2R-GM11b. I did a little digging and apparently the harness was changed after 2007, though I had been told all Cobalts had the same one up through 2010. I've looked extensively and I can't seem to find any other interfaces that reference application to any models past 2007 except some with OnStar. Am I missing something? Is it possible I could use an OnStar capable interface in my car even if I don't have it, or is there a part that will fit and I've overlooked it? Is there a generic/universal alternative? (I've heard Metra makes one but that it doesn't work for Cobalts for some reason) I'm quite lost at this point, and I really don't want to waste my money/time guessing.