TXV Valves

Thermostatic expansion valves, also referred to as simply expansion valves or a

TXV valve

work to control the amount of refrigerant flow into the evaporator. TXV valves are nozzles that simultaneously drop the pressure of the refrigerant liquid, meter its flow, and atomise it sending a low pressure and temperature liquid suitable for cooling to the evaporator from where it is blown into the car's interior.
If you are suffering no cool air or insufficient cool air you may have a defective or blocked expansion valve. There are plenty of options when it comes to TXV air conditioning expansion valves, so make sure you select the right one for your specific car.
 

Control Valve

Your AC control valve is the regulating nozzle that meters the flow of refrigerant to the evaporator.

Control valves

, as well as preventing the evaporator from freezing, control the flow of cool air in the car. Bulb pressure opens the valve the higher you turn your AC, allowing more cool air to flow, whilst the evaporator and a spring restrict flow by closing the control valve when the AC is turned down
Clogged or damaged

control valves

will restrict the amount of cool air and need to be replaced. Quality

control valves

for any car are readily available at Eurocarparts.com.