Intermittent Electrical Problem – Damn!

[Chevy1966]

My 02 Suburban just started dropping codes U1000, U1064, B2973, B1477. Along with this the vehicle would not start AND all power was shut down to the accessory bus. The worst part is that this is an intermittent issue – truck will run fine for a few days, then just when I start to think the problem healed itself, the problem presents again, usually at a very bad time. I really didn’t think this was simply a battery problem, but I did install a new battery – of course that didn’t fix anything. I’m not even sure where to start short of replacing the ECM and every wire and other component that has a wire connected to it. Has anyone had the same set of problems or seen these codes? Help!