406 no power to air con control unit

i have a 406 1.9 tubo intercooler diesel s reg 1999 model there is no power to the air con head unit and the fuses are still intact is there any switches or realays i can check could you please point me in the right direction please....

i had a pro look at the aircon it cost me 35 quid for him to look at it. He told me it needed a new power suply and a relay from the ignition barrel. That cost me 60 quid but it all works now.