I driving and my truck just cut out

I driving and my truck just cut out. It cranks no spark no fuel pressure, pump doesnt prime.I dropped the tank thinking it was the pump, bench tested the pump it was good. Before that I did check fuel pump fuse under dash fuse for fuel pump under hood. The relay iswitched with others, they all click.I realized the PCM fuse was blowing when I put the key in the 2cnd position. Checked all the wires to pump o2 sensors. After reading up on it, looked for hours for trouble with wiring all looks good.I tried a test with a circuit light on the negative terminal of the battery with the cable off and the light hooked inbetween. The light stayed lit while I pulled every fuse until I pulled the GEM under the dash it went out. Turned key the pcm blows instant. Any knowledge of this problem will help thank you.