i have searched the archives endlessly but but i can't find a related problem.
i took a short trip yesterday and my car was running great.....after a stop at the store it would not restart. it will crank but it will not start. after getting it home i discovered no spark, no fuel. all the fuses are good even the ones under the hood. when i turn the key to acc pos. i get nothing no lights, check eng. brake, selt belt etc. and the fuel pump does not prime. i jumped the aldl a-b terminals and nothing happens...will not blink fans will not run pump won't prime. i used an ecm from a friends car same eng.& trans 5.7 auto and still nothing..... any help ggreatly appeciated!!!!!

 

It really sounds like that 20 amp fuse really close to your battery went out. That is exactly what happens when it does. I hope thats it.