A quick overview how your air conditioning operates:
The majority of air conditioning systems in today’s cars have the following major components: a compressor, a condenser, an evaporator, and a pressure regulating device like orifice tube for most Ford or GM vehicles, or a thermal expansion valve, commonly used in imports and aftermarket kits.
The compressor is a belt driven pump that is fastened to the engine. It is responsible for compressing and transferring refrigerant gas. The condenser is where heat dissipation occurs. Condensers must have good air flow anytime the system is in operation. Located inside the vehicle, the evaporator serves as the heat absorption component.
The evaporator provides several functions. Its primary duty is to remove heat from the inside of your vehicle. A secondary benefit is dehumidification. Controlling the evaporator temperature can be accomplished by controlling refrigerant pressure and flow into the evaporator. Many variations of pressure regulators have been introduced since the 1940’s, like the orifice tube and thermal expansion valve.