Thunderbolt,
As a fireman, I can tell you that unless you have the original wiring diagram from the factory, the accessory wiring is going to be a pain to find a schematic. If you find the chasis schematic, you may be able to trace the accessory wiring from there. The good thing is, like our 46 dodge, the wiring is very basic for these old fire trucks, not all computerized like today's.
