Cruise control on late '90s XJR

If it is an XJ6 then cruise control has the buttons on the right -

0706269616142 If it is an XJ8 (late 97 onwards), then the cruise control consists of a button next to the gear shifter (typically you'd have two buttons here, sport and cruise - but not all cars have both) and buttons on the steering wheel for set/resume/etc.

Matt