I don't think you'll find an ODB2 connector on a 1999 George Boy Cruise Master Diesel. Probably on a freightliner chassis. It will have a plug in the engine compartment and also somewhere around the steering column/dash where you can plug in a cable to run VMSpc. This will not be an ODB2 connector. VMSpc is what I use, and really like it.
Fred
Fred & Vicki
St. Augustine, Florida