air conditioner intermittent

First of all, if you needed to have refrigerant added, you would need to figure out why. Refrigerant should not be missing, it does not get consumed like a fuel. It is permanently in the system unless a leak occurs which must be repaired. Now if the air conditioning system does in fact work - yet intermittently so - then refrigerant level would not seem to be a problem, at least primarily. You'll want to focus attention on the electrical portions of the system - the cycle switches, the compressor coil and clutch, the condenser fan, the interior climate control components like a temperature blend door actuator and the temperature controls. Use this link to find some shops near you that can help with your concern: www.repairpal.com/repair-shops