99 Kenworth W300 Won't start. Need wiring info.

Had a similar problem on my 99 W900!!
My problem ended up being the ecm not getting power,,,,
On the fire wall their is a square plug with 40 or 50 or so wires going through it,,,the larger red on the bottom right side (if im remembering right) is the power to the ecm,,,,
On mine,,the problem wasnt on the engine side,,,it was a corroded terminal on the harness from the cab side that goes into that square plug.
Maybe give the harness a shake while someone is turning it over and see if it fires up!!!
On my W9,,their is a circuit breaker at the very bottom of the fuse/breaker box (2 prong silver circuit breaker,,think its on the 2nd row at the very bottom),,check there for power also,,if you have no power there,,,you'll have to dig deeper!!! Hope that helps some!!!