Hey all. I've got a '99 1500 z71. I hate the auto locking doors more than anything so I did some research and it seems that replacing the BCM with a later model unit (00-02) is an easy way to get the ability to change that function. So I got a 2000 BCM and put it in. Truck won't start. I look around some and finally find this page.
GM Computer Relearn Procedure (including Crankshaft relearn)
I do the "reset" exactly as instructed. 11 minutes with the ignition on, 30 seconds off, repeat twice more. The battery went dead before I finished. Got the battery charged. Now it's snowing and I went through the process again and it STILL WON'T START! And here's a nice little bit for you: putting the original BCM back in doesn't fix the issue!

This is actually my second attempt. last time I ended up putting the original back in and messing around with the ignition for a half hour or so just to finally have it start up fine and all was good. I'm trying to get it working with the new BCM this time though! What is the trick?