[bell]

The newer gm trucks/cars are nothing like pre-2000 ones........The 2007 gm trucks use data wires to control the ignition/starter/etc, not the typical key cylinders......
is there and aftermarket alarm/remote start on the truck? It is rare but I've seen the aftermarket interface modules you need top use for remote starts fail and cause similar prpoblems......

I'll log into a program I have on my comp in a bit (currently on my bb) and see exactly which data system that truck uses....
But could be anything from a bad "body control module" to a failed key switch.......when the data wire systems fail things turn to **** all at once.....