2002 Cadillac Escalade Doesn't start

A few weeks ago, truck didn't start. It was not a dead battery as all components worked. Turn the key, everything lights up and sounds as usual, but nothing. It did not even attemot to start. After about an hour, it started right up. Everything was fine until last week it happened again. Today, truck doesn't start at all. New battery. Enough power to run all components. Truck does not attempt to start. I can hear the starter relay clicking. Purchased new relay, but still no start. Originally believed it may be an issue with the Passlock system. I attempted to bypass Passlock with negative results. Haven't had the starter checked yet.

It feels like a security system issue to me. Like an ignition lock, however, if the relay is getting power I'm inclined to think that the computer does not believe it is being stolen and is allowing the truck to start.

Any ideas?