The chassis wiring information would come from the chassis maker.
The only wiring info you are going to find on the coach is in the owners guide. In the guide you will find 12v fuse panel info on page 102 and 103. You can get the guide at the National Yahoo group site. File info on the left side of the page. The owners guide for 98 and 99 tradewinds is there. You have to become a member to access the site info. NationalRV : National_RV