The handbook refers to upper and lower lumbar supports and the little four way button works, but the support all seems to be low down? Is it that there are two bladders - one at about belt level and one just a bit higher? The I press either the 'up' or 'front' part of the button it feels like the same bits inflate? I'd be grateful for some clarification on exactly what is supposed to happen. As in my earlier post, mine pump up and go down when I press the 'back' or 'lower' part of the switch but then very slowly go down again - so I suspect I have a small leak (it's not that long since yet another birthday! ) or a faulty valve. Can the valve be stripped down and cleaned?