air con stopped working

my air con stopped working whilst driving. the light on the dashboard switch will not illuminate when the button is pressed. ive never had a problem with air con before so i dont know exactly what to look for. is it just the one fuse under the bonnet? or are there others or relays i should check?

Most aircon systems have a pressure switch which prevents the system operating if the gas pressure drops too low, a recharge may be the answer.