I can't speak for Freightliner, but Spartan Chassis will sell you a complete electrical schematic -- specific to your coach! And that document contains ALL the wire color codes and fuses and circuit numbers for the Spartan Chassis. You send them your VIN number and some money, and they'll send you the electrical manual. I have a pdf version for my 2008 KSDP -- it's 125 pages!
I looked in my electrical manual to see if maybe I could find a similar wire, but couldn't. The highest wire number in my coach appears to be 1209, and I only found a very few multi-color wires. Almost all my wires are a single color.
Unfortunately this electrical system manual is ONLY for the chassis -- not the Newmar body. So if this wire is part of the coach body, the chassis electrical manual won't help.
So far, I haven't found such a detailed electrical manual from Newmar for my coach. I sure wish I had one.
P.S. If your wire is really cut in the middle -- you can easily splice it back together. I recommend the appropriate sized crimp butt splice -- with waterproof shrink tubing.
Don't solder. If the splice were to heat up, the solder can melt, and leave you with perhaps a hot wire floating around.
Either get the butt splice with built-in waterproof shrink tubing attached, or get some waterproof shrink tubing (a.k.a. Thermoset adhesive -- Anchor brand at marine hardware stores is great) and put it over both exposed ends. Once properly crimped and heat-shrunk, it'll be 100% waterproof, dustproof, and should be as good as the original solid wire.
Woody & Sandy
2003 Chinook Cascade
2008 Newmar Kountry Star 3623