98 Tahoe 5.7 4x4

When the key is in the "run" position or the "accessory" position several fuses don't get power - hence things don't work. No power windows, no wipers, no radio, no fuel pump relay - pretty much everything that you would need to be in one of those two positions to work. Truck starts and runs good once oil pressure is up enough to bypass the fuel pump relay.

At least my many issues seem to have come down to one common issue.

Any suggestions - I've read about contacts in the ignition corroding? What can I do about that. We have replace the ignition cylinder, but that's it as far as steering column components.