Air Flow and the Condenser
This question reminds us of how important it is to maintain air flow through the air conditioning system's condenser. The condenser receives high pressure high temperature vapor from the compressor and releases this heat into the cooler air passing through its fins.
When air flow through the condenser is restricted, reduced air conditioning performance will be noticed. This is often caused by a faulty fan clutch, or no operation or weak operation of the electric fan. Road debris will clog the fins of a condenser reducing its ability to exchange heat. Cleaning these fins will often restore flow through the condenser fins and air conditioning performance.
As shown in the illustration, the condenser and the radiator are close. Air flows through the condenser and then radiator. An overheating engine will reduce the condenser's ability to function, and many PCM's prevent compressor clutch operation if the engine is overheating. A frozen expansion valve prevents the flow of refrigerant in the system. This is caused by moisture and once frozen, reduces performance at all speeds.