Auto Lock-Unlock on 04 S-Blazer

I just took delivery of an 04 S-Blazer. When I drove it home I noticed it locked the doors when I put it in drive and unlocked them when I shifted into park. My 2000 S-Blazer doesn't do this. I would guess that it's PCM based programing. Does anyone have a service manual or info on how to activate this on a 2000? Would I need a tec-2? Is there a special programing mode for customizing various features?

Thanks for any help,

Leif

04 S-Blazer 4Dr 4WD
00 S-Blazer 4Dr 4WD

You can't do this on the older ones... The programming in yours is raddically different than the 2k....