Thank you for the contributors to my question. I had to disconnect the BCM several years ago because it was causing a battery drain. After unplugging it, the battery drain stopped. So now, I have 2 things unplugged: siren and BCM. Perhaps, I should plug the BCM or replace it and see if the fab lock/unlock the doors.
Thank you ala_Xfire of providing the schematics, they are very helpful. You asked about the 2004 crossfire, I had it for about 7 years and it has currently only 70K miles. What do you think it worth now?