1994 GMC Sierra Pickup, Fuel Pump Inop

I have 1994 GMC Sierra, the fuel pump will not come on when key is turned on but will work when directly connected to battery. We have checked all fuses that we know of and they are good. If you pour gas into throttle body the engine will fire and run for a few seconds. We have been trying for a week now to figure out what may be wrong even replaced the computer and fuel pump relay can you help?

1994 Pontiac Bonneville No Power To Fuel Pump

My 1994 Pontiac Bonneville died put a new fuel pump in ran fine for a couple weeks, then stopped. I took it back to the garage, they said no power at the pump.  They checked all  the fuses and relays and said where fine but no power to pump I don't now what to do now!