Hmmm. Thanks for pointing out my misconception. I thought the amp power was supplied by the radio. It's not. In my '99 service manual, on pages 8W-47-7 through 8W-47-9, it shows the power for the external amplifiers on the front door speakers being supplied from the Radio Choke Relay, which is fed from fuse 4 in the junction block on the left side of the dash board. It also shows the rest of the speaker wiring. If you can supply more information about what you are trying to do, and what was in the truck originally, I'll try to help. Obviously, if your truck didn't come with the 'premium' (infinity) audio system with the tweeters, it is going to take some work. Were you planning to add the tweeters on the pillars also? Did you get all the speakers with the radio?
Tom