seat recliner 2015 kingham

hi,we own a 2015 kingham.it is fitted with isri seats and fitted with 2 arm rests and swivel bases.
it has 2 knurled wheels on the side the front one tilts the seat forward and back,the rear one
turns a bit but nothing else happens.just wondering if these seats recline or not.does anyone else
have these seats fitted,thanks.

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There are exploded diagrams and parts lists at the link above that might give you a clue. The list is in German but Google translate will help.

Could the other adjustment be for lumbar support?

thanks,will look next time i'm in the van.