Jfile,
I don't have the answer, but I can tell you where to get it. This site is dedicated to car stereos, alarms, cruse control installs, etc. http://www.the12volt.com/installbay/default.asp
You can join for free and do searches without joining. There will be someone who can help you out with this problem. They also have a wire color code lookup that is pretty good. If the vehicle is newer than 2000, you have to post a question an one of the folks will give you the answer. I had to on my 2002.
Hope this helps.
02 2500HD LT Dmax/Alli CC 4x4 Lt Pewter, Tan in, Amsoil, transynd, Bilsteins, Amsoil Air Filt, JK 4\" Exht, RollnLock, Rhino Liner, Remote start, alarm, High Idle, SPA DG211, Pred, Mega, Fumoto, Remote oil bypass, XL Tranny cooler, XM, Cell kit