Michael-
My "Monterey 2006 Wiring Diagrams" spiral binder has most of my coach's systems in it, both 12volt and 110volt. As far as chassis goes, there are some basic diagrams for that as well, but probably not everything you might run into. Additionally, Monaco included many schematics from the 2005 year since they were unchanged. That said, several of us that own these coaches have run into some wiring that doesn't fit the schematic as drawn, reflecting the manufacturer's reserve to modify installation procedures as they build.
Below I list most of the diagrams in my binder:
Engine Start & Door Seal; Cruise Control; Brake Lights, turn/hazard; Entry Step; Velvac Mirrors; Power Visors; ABS/ATC; US Gear Prewire/tow brake; Dash A/V components; Exhaust Brake; Keyless Entry; Main 12v Distribution; AC Distribution/240v Main; AC Distribution/120v/Inverter; Aladdin Sensors; Multiplex System; Televisions and Audio Video Components.
Many diagrams, such as for 240/110v and A/V components etc., have multiple pages because each model of Monterey (Laguna, Ventura, etc) is wired slightly different; so there are a lot of pages that don't apply to any one Monterey. To answer your last question, the book does not have a "number". Occasionally I run into something that isn't in the book. Usually it relates to a component supplied to Monaco by another manufacturer, such as AquaHot or Catapillar or Fantastic Vent or Dometic, etc. etc. That is understandable, so if you have an issue with an independently built feature, you will still have to go to that manufacturer to get assistance and/or diagrams.
Nevertheless, it is certainly much better to have the diagram binder than not. Mine is yellow and 17" X 11", so if Northwest has one for a 2005 Monterey that they verify is that size and spiral bound, go for it. I am sorry that I have yet to scan or photograph mine for the Coach Assist section of the club website. It is my intention to do so, as your isnt the first red flag regarding this era and model of coach. It is sad that so many coaches are resold and the previous owner didn't include all the manuals in the deal. I'm not sure what good they are left at home, or what good they are to someone that no longer has the rig. My Monterey's documents all go wherever my coach goes; they may come in handy 1000 miles from home, and literally have more than once.
If there is a specific schematic you need right away, I'll try to get a photo of it to you.
Joel