You don't give an engine size but there are no emergency shut offs on any chevy light trucks.
Why are you looking for an alternative method to shut down truck maybe I can help
What engine do you have?
Need VIN code 8th digit of VIN code
I would start by checking the fuse box under hood 2 fuses in particular (marked ) Eng 1(10 amp fuse) and ECM B(20 amp fuse).
If fuses are good check the fuel pump relay (located in the same fuse box).
Is the a dual tank truck?
Next thing to do is check for power on the gray wire as close to the pump as possible .
Also check the fuel pump ground.