http://www.cdr-roc.com/89JD/89-JD-Chassis-manual.pdf

(large file 900+ pages, 336 Mb... it will not upload here, I hope the link lasts)

Thanks! Mine is a 94 Oshkosh but this is the only thing I have found so far. Hoping this will help me get some botched dash wiring repairs done.

Welcome to the site Mike. The Oshkosh Regals were late in Barth production but we have some info here. Search around, good luck.