Originally Posted by Guitarist575

Sorry to bump such an old post...
I finished the alarm installation a day or two after my last post on this and thought it might be good to post the solution here for anyone else with the same problem.

The correct wire is the white one towards the right of the harness on the ignition control module. I'm pretty sure it is the 5th one from the right.
I got a hold of GM's techline software and looked it up in there before trying. I didn't even have to touch the PCM.

Also on my alarm (not sure if they are all like this) it won't start unless the parking brake is applied. I just tricked mine into thinking the parking brake is always on.