'98 tahoe fuel pump electrical problems

i've replaced my fuel pump, thinking that wasnt the problem. i've determined it is not getting power. although sometimes it does. im thinking it is a short somewhere. does anyone know where i can get a schematic for my vehicle, or have any idea what it might be. i was thinking the relay, but why would it work sometimes??? i also used electric grease/lube whatever on the pump connectors, and tried wiggling those, but that didnt help. any specs, voltage, amps, ohms, anything to check will help.

i would check the relay to be on the safe side. i'm having fuel problems with the one i just bought, relay check is definately on the list. but one thing, do you hear the fuel pump wind up?