Please help, automatic delayed door lock 2003 Silverado.

Hey, my friend just bought this 2003 2w extended 5.3L silverado. The truck has a basic package, no power accessories except power door locks. The problem that he is having is that the truck automatically locks the doors by itself when you start driving it, and then when you want to get out from the car you have to use the button to unlock the car. We looked in the manual that came with it, and there is a sequence and procedure to remove that feature, since it is quite annoying. Does anyone know how to disable it?? please help.

You mean it doesn't automatically unlock once you stoped and put in park? Or do you mean stopped (idleing) while still in drive?

R T F B

rrousou: RTFB my ass!
i read the book few times, and did what it suggests to remove/disable that option. It works, confirms that it has been disabled, honks once, 30 secs passess locks then unlocks................ and nothing, so before posting RTFB, ask me if i tried and red the book.

skipr: no it doesn't unlock when i put it in P, it only unlocks itself when truck is turned off, it only locks itself about 5 secs after D is selected.
I would like to avoid going to the dealer if i can in order to deactivate that feature. I read somewhere that there is different sequeces and procedures for different years, maybe mine is different?

What i did to disable it:
pull high beams, turn on ignition, press unlock and lock, it sounds horn, press unlock three times, turn off ignition, 30 secs passes, truck honks once, and locks and unlocks itself.
Again,its a 2003 5.3L exteneded with long box if that matters, 2wd