There are several reasons why an Automobiles AC Might not cool when in a stop and blows cool Just when moving. To get more detail about Air Conditioning you can visit http://thecomfortauthority.com/.
The most common explanation is that the cooling fan for the condenser isn't working. It's important to understand that lots of times the cooling fan is shared with the radiator and condenser, other times there are TWO distinct ones. The reason a poor cooling fan can impact the AC so radically is how heat from refrigerant (Freon) is normally cooled when passing through the condenser.
Therefore, even if the condenser fan isn't working, it might not affect the AC while the vehicle is moving at highway speeds. This is because air is passed through the condenser when driving down the street so the fan isn't needed.
When the vehicle reaches a halt, the condenser is wholly determined by the cooling fan to cool it down. At times the cooling fan may be functioning, but it could be moving too slowly to sufficiently cool the condenser.
To confirm the motor, a test light may be used to verify it's getting ground and power to the electric plugin. If ground and power is present and the engine isn't functioning, the engine has an open circuit.
Other Reasons for Automobile AC Not to Cool in an Idle or a Cease
Heat transfer from the radiator into the condenser can change efficiency if the vehicle is overheating.
The AC compressor might not be pumping satisfactorily at slower RPM's (revolutions per second).
An expansion valve might not be regulating the refrigerant correctly.