Patrick517

My brother has a 09 1500 and all of a sudden has a no crank no start issue. I am a peterbilt mechanic and I'm pretty fluent with just about all vehicles but this one has me a bit stumped. My brother thought it what the security reader for his key and replaced that and the ignition tumbler but no change then he put the original parts back in. When keyed on all dash lights come on as if the systems are powering but nothing. I jumped the starter relay and truck would crank but not start. It almost seems like the ecm is not powering up. Anyone come across this issue before?