You start from the rear passenger side, then goto the rear driver side, then to the front passenger side, and finally the front driver side. You always bleed the from the farthest point away first, then gradually move your way closest to the master cylinder.
Your 1997 GMC is equipped with a Kelsey-Hayes 4WAL brk. sys.
The sequence Chris told you is correct but be aware that it may take up to 2qts. of fluid & needs to be ran through a [function test] to purge the air from the ABS unit.This can only be done with the use of a scan tool.(eg.OTC4000,TECH-1,TECH-2 or equivelent)
Technically yes, but through past experience it can be done without a scan tool. By shorting pins A&H on your DLC (DATA LINK CONNECTOR),under the dash you can display flash codes& cycle both solenoids.