Who do you call when your air conditioning stops working?
If your AC unit breaks the best thing to do is contact an HVAC contracting company. They will send over one of their Air Conditioning Repairman to take a look at your heating and cooling system. You should wait until the repairman gets there before you decide to touch any parts of your HVAC system. You run a high risk of further damaging you air conditioner if you try and fix it yourself.
Once the HVAC repairman arrives to your house the process is quiet simple. All you need to do is show him where your air conditioning unit is and explain the problems you are having. The contractor will then be able to diagnose your heating and cooling system. Before you make any decisions on replacing any parts, be sure to check and make sure your unit is no longer under warranty.