2002 Yukon no power to fuel pump

[myoldmetal]

The problem isnt the Napa pump. The problem is the the truck is not sending power to the pump. I have swapped the relay, and done the wire shake. in fact, I removed the under hood fuse box so I could inspect the plugs and ECU, and also traced the harness under the entire truck.....still no signal to the pump.
Thanks for the diagrams clinebarger. I was able to get a hold of these when I dropped the tank the second time, and I held the test light on the wiring while someone else turned the key on to make sure I csught it within the 2 seconds.......nothing. next I will be unplugging one of the injectors to see if I have a pulse at that loction, and see if I can narrow it down from the other direction.