99 GMC Sierra - Factory Alarm Disable

How do I disable the factory theft-deterrant system on a 1999 GMC Sierra?  There is supposed to be a sequence of events that will stop the factory alarm from honking the horn if the doors are manually unlocked after they are locked via the remote keyless fob, but I can't find it anywhere.

I appreciate any information.. .Thanks in advance..

Is it factory Keyless Entry u are using. because u should be able to disarm it by the lock switch or the igntion turn on.  If it is aftermarket keyless then u should hook up the arm/disarm wires

BCM (under drivers side dash) third plug, on the right ( when looking at it) Green wire is disarm, Tan is arm.