Laguna II a/c and heater controls

Afternoon all,



I'm well aware of the chequered electrical past with the Laguna mk2, I picked one up yesterday and the buttons in the middle of the heater knobs don't seem to work.



So that works the a/c, heated rear screen and the recirculate setting for the blowers. Should they light up when pressed?



There are lights on the panel working as they should, and the twisty knobs do work the heater as they should. (Although it blows lukewarm at best)



Where's the most likely fault to effect apparently all three?



Thanks,



Gaz