Depends on what the fault is? You don't say. If it is not getting cold it could be quite a lot so things including lack of refrigerant (Caused by a leak?) or any of the components.
Having said that, air con is not really a DIY proposition as you need a specialised (expensive) machine. It is also illegal in the UK to vent the refrigerant to the atmosphere - another reason for the machine.
t, May 2007
