The full manual set sells for over $300. I've heard that they are out of print now.
There are sources for the manuals on CDROM out there at a much more reasonable price (~$40), which I believe is compiled with some additional useful info.
Try this guy:
jim928@ptd.net
I'm pretty sure that address is still current and I believe he has some other 928 lit that he's compiled to CDROM.
Sorry it took so long to get you an answer, didn't even realize I had the spare switch and for some reason I though I'd have to pull the whole door panel to look at mine.