If you don’t have the on/off switch on your dash, then your passenger seat has the passenger sensing system which enables the airbag if a properly seated passenger is present. If no passenger is present, no airbag deployment. Some lower trim levels, WT, etc. may have the on/off switch, but I have never seen one in a K2. And K2XX is the assembly code for the platform on which your truck is built. ‘99-‘06 trucks were built on the GMT800 platform, ‘07-‘13 trucks on the GMT900 platform, ‘14-‘18 trucks on the GMT K2XX platform, the new platform for ‘19 and beyond is GMT T1XX. I tell you all that only because you will see those codes thrown around on the forum as a reference to a certain generation of trucks.