On a 2005 GMC Sierra 1500 4x4 can I modify the auto 4wd button

I wouldn't! All that stuff is computer controlled and God help you if you start cutting and splicing into the wiring harness! What I would suggest is a simple toggle switch that shuts down the fuel pump when you flip the switch. Find the hot wire going to the fuel pump and wire in your toggle switch. If someone does get the engine started it'll only run for about 30 seconds with the toggle switch off. Hope that helps! Jim

I know what you mean about cutting into the wire harness and it being computer controlled... But I don't want to add a toggle switch because they're easy to find, if anything I'd install a push button because it's a little more concealable... I was just wondering if it was possible to do it like I asked because I've never seen or heard of it being done... I'm not sure if it's because nobody has thought about it or if it just won't work that's what I'm trying to find out before I start cutting into it or anything like that... Also I was planning on probably doing 2 "kill switches" one for the starter and on for the fuel pump... My only problem with installing a switch is finding a location to hide it that's not easy to find...