fuel pumps go out usually without any notice whatever. Just check all electrical connections first before replacing them. Its a lot easier to check before hand. I once had a pump malfunction, hearing no turn on when the key was on and it turned out to be a cracked fuse block. Who would have thought.

 

I had a similar problem with the fuel pump and electrical problems including the turn signals, dome lights and backup lights.

After rerouting the fuel pump wire from the f.p. relay, under the chassis, to the rear (to at least get it to run), I traced a short to ground condition located right below where the drivers foot is usually placed...particularly the heal of the foot.

Chevrolet places the bundle of wires that go to the rear of the vehicle right under the driver's foot...it is just a matter of time before the wires wear through and you have all kinds of weird electrical problems. I know this problem exists in other Chevy Blazer rigs too because I checked several at the wrecking yard and saw the exact same wiring problem.

BTW the fuel pump wires go through that bundle too and it also involves the HORN DM circuit. Check under the driver side carpet for burnt wires and especially damage to the wiring bundle. It's not that difficult to check, just unscrew the plate holding the carpet down and yank up the carpet...just do it far enough that you at least find the wiring harness..i had to feel under the carpet to find the bundle - it smelled strong of burnt rubber and plastic and so i knew i found the short. The bundled wiring harness just crumbled apart when i touched it.

good luck,
b.knuckles