You have taken off the cleaner head and looked there where the tube goes into the machine?
Next would be to remove the small concertina side pipe as they block up there.
If no suction from the wand, there is a perspex wheel that operates a changeover valve that activates when you lift off the wand. Make sure it is operating and clean the moving bits of that mechanism and lubricate it with something like dashboard shine or Mr Sheen.