Just to close this post out.
Found my missing PacBrake wire and reconnected all is good. The TK-1 Relay on the Monaco Drawing is part of the Midland Grau ABS Brake Controller, it supplies 12VDC to activate the PacBrake. Other parts I was looking for; the VIM was located under the Allison Shifter along with the Allison Control Box.
I now know more about my coach, PacBrake, ABS and Allison.