Got a buddy of mine, older fella, who has zero mechanical knowledge. All he knows is turn the key and go. Well recently his radio stopped working all together, truck on or off, and when you remove the key from the ignition nothing on the truck works at all. Its as if when you remove the key you're cutting all power to everything on the truck. No lights, no horn, no door locks, nothing.... But, when you turn the key to the ON position, or back to accessory, all power is back. Checked the obvious fuses first then after seeing those weren't bad, we pulled just about every fuse out of the panel and didn't find any blown. Found some stuff on google that says fuse number 51 is blown but upon inspection, it looked fine. Does anyone have ANY idea whats going on here???

Again, Key on or at Accessory, everything work but radio. Truck running, everything works but radio and lastly when the key is off or out of the ignition, nothing work at all.

 

There is a timer that cuts power to protect from draining the battery. As far as I know it only monitors if the interior/exterior lights are left on after the key is removed. I don't know if this cuts power to the locks and horn as well, but it may be worth looking into.

 

turned out it was a corroded, frayed wire underneath of the fuse block under the hood. fixed and everything is good now.

 

Stranger Ranger.
I'm experiencing the exact same thing with my truck.
Do you remember what wire was corroded under the fuse box?
Thanks

 

Probably all of them. The '03s never came with a cover under the fuse box, like the newer trucks, and they are notorious for corrosion there.