1999 Sierra 1500 pos. Fuse Box Problem

[ph0t0bug]

I had trouble with my truck last night while driving down the road the engine killed and would not start back up. I have done testing on the Fuse box and from what i understand is that 87 goes to the ECM fuse 20amp which is good and there needs to be constant power to 87 from that fuse. I found that I do not have constant power to 87. in fact i have no power to 87 if off or key on. The pics kinda explain what Im trying to say. I was wondering if its the Fuse block and where can I find out how to remove the hood that surrounds the Fuse Box... Thanks ahead of time for any help you can provide.

[8.1HD/ALLISON]

Need to remove the 4 bolts that hold the drivers fender brace. Then you can trip the little tangs and get to connectors on underside of fuse block. Mice love the underside of the fuse block. I would inspect wiring closely.

[ph0t0bug]

Headed out to do it now...Thanks.

[8.1HD/ALLISON]

No prob let us know what you find.

[ph0t0bug]

ok... I looked and did not see any wireing problem under the box. Im going to check the rest of the wires today. I found that even though the diag. say that 87 goes to ECM B but in actuality 87 goes to the PCM unit. Thus all I could think is that there is a problem with the wire from 87 to the PCM or... which I PRAY is not the case, the PCM its self. I did find out that the PCM provides 12v constant power to the FP Relay on 87.

[ph0t0bug]

Im goning to go ahead and change the fuel filter and see what happens... I doubt this filter has been changed in 14 years... I know I havent since 2005....

[ph0t0bug]

Was not the fuse box. A note to anyone working on a 1999 GMC Sierra 1500 4.8.... the pin 30 and 87 are reversed from a lot of videos out there. Constant power will come from 30 and go to 87 which goes to the fuel pump. That all being said it was in fact the fuel pump. Was able to get one and it turned over and started after replacement. Thanks for the help 1HD!