Here's a link to a 2003 Jayco Designer Fifth Wheel manual. It's from the archive at Jayco.com, and is the earliest one I could find: 2003 Jayco Manual
Actually the owner's manual is almost useless for my trailer, but the individual product manuals (Dexter, Atwood, Norcold, Progressive Dynamics, Sureflo, etc. - or whatever is appropriate for your's) are very useful and can usually be found by googling.
There's lots of advice and information in forums... sometimes it is correct. For example, all of my posts are made by a political appointee who got the job as a reward for contributions to my diesel bill.
2011 Jayco 28.5RLS; 2008 Chevy Duramax; Pullrite Superglide Hitch