Ok, so from searching I have gathered that if the A/C gas pressure is low, the fan will not come on.
Is there a way to test the pressure? Or should I get a mechanic to test it, and if so, what should the pressure be?
I got the A/C regassed less than a year ago though, as the fan played up and some switches were changed.

The other possibilities are faulty switches, or a faulty fan.
Is this correct?

Can anyone tell me the easiest thing to diagnose and how to do it?
Thanks