i need a certified gm tech's help

[busa4]

i bought a 2001 gmc sierra and the engine wiring harness was cut at the fuse block. i purchased a replacement connector and a bunch of pins to wire it back together. my problem is i cant find a wiring schematic for the engine harness. ive called 2 dealers and they were not willing to give me this info.
if any techs are on here i really need your help. i would be most appreciative.
last 8 digits of the vin are 1Z179139
thanks for your help.