GM-GMC: no pwer to fuel pump, gmc suburban, gray power

Question
I have a 1994 GMC suburban and i am not getting any power through the gray power wire. i have tried to track down the problem  but i have not found it ...still wont start does anyone know of this kind of malfunction? and what can i do to get this fixed?... i thought about taking the gray wire straight to my battery would that work?  please help me!!!!!

Answer
The fuel pump is fed power through a relay, the control side of the relay is fed through a fuse from the ignition switch/pcm.  When the key is turned on, the relay is energized for 2-3 to prime the system. When the key is turned to the start position the pump turns on and stays on as long as the key is on and there is an rpm input to the pcm.  I will attempt to locate a good schematic and help with location and wire coloring.  hope this helps