I think the Southwind is on the John Deere (Oshkosh, later bought by Freightliner) chassis. If so here is a link to a parts book. http://jdpc.deere.com/jdpc/pdfs/PC2109.pdf
Freightliner used to be able to look up parts and had them. It has been a few years since my friend sold his JD based rv so I am not sure if they still help or not.