Normallythe jacks are added by the coach manufacturer. You should also give the make of the jacks to help with the answers. Someone on here must have one like yours and can be a big help. There is also a good chance the P.O. had a problem with the jacks and that is why the fuse got pulled, or it blew and he couldn't find it. You can also check the jack manufacturer on line to see if the fuse is shown there.
1995 Roadtrek 19 Versatile
1975 GMC Eleganza II