How Does My Car’s A/C Work?

What was once an optional creature comfort on high-trim vehicles has become a must-have in any vehicle, especially in regions with hot summers. For most of us, it’s hard to imagine going a summer without a working A/C system to keep the cabin cool and comfortable.

Our reliance on this system may leave you wondering, “How does it work’? Sure, you turn the knob and out comes cold air, but what goes on behind the scenes that allows our vehicles to produce ice-cold airflow on even the hottest of days?

In this article, we’ll cover the various components of your air conditioning system and how each plays into delivering cool air through the vents.

Rear air conditioning vents

What Components Make Up a Car A/C System?


Your A/C compressor is the heart that drives the entire system. Driven by the accessory belt on the front of your engine, compressors take in low-pressure air from the surroundings and compress it to a highly pressurized state. 

A/C compressor sitting on workbench


The condenser is responsible for taking refrigerant in its gaseous form and cooling it down until it reaches a liquid state, all while keeping it at high pressure. These work similarly to the radiator used to reduce your coolant’s temperature. As it sits at the front of the vehicle behind the grill, the condenser makes use of the air forced into it (either by the vehicle’s movement or a fan) to conduct heat and transfer it away from the refrigerant. 


Evaporators act almost as the opposite of a condenser, taking high-pressure liquid refrigerant and changing it back to a gas, which causes a cooling effect. Cabin air then flows across the evaporator, lowering the temperature and creating cold air to be blown into the cabin. 

Expansion Valve/Orifice Tube

There are two types of components used to control the amount of refrigerant introduced to the evaporator. Which component your system uses is entirely dependent on the model and year, although both accomplish the same thing.

When moving refrigerant into the evaporator, the pressure of the refrigerant drops rapidly which causes the temperature to drop as well. 


The receiver/dryer takes high-pressure liquid refrigerant from the condenser and uses a desiccant, or a drying agent, to remove any moisture accumulated from condensation through the process. 

How Do These All Work Together

Now that you know the basic components that make up your air conditioning system, it’s time we look at how these specialized parts tie in together to provide you with that precious cold air. 

  1. Cold and low-pressure gaseous refrigerant enters the compressor and leaves as a high-temperature and high-pressure gas
  2. The refrigerant is then sent to the condenser, where it exits as a cold high-pressure liquid.
  3. Liquid refrigerant is sent through the dryer, where the moisture is removed
  4. Expansion valve reduces pressure and introduces refrigerant to the evaporator
  5. The evaporator turns the refrigerant back to a low-pressure gas, causing a cooling effect within the evaporator
  6. Air is blown over the cold evaporator, where heat is drawn away and comes out as a cooled flow of air for the cabin

Common Causes of A/C Failure

With this complex process taking place anytime you want cold air, you could imagine there’s some room for failure within the system. Here are some of the most common issues to occur within your air conditioning system. 

  • Refrigerant leaks
  • Clogged or failed condenser
  • Faulty compressor clutch
  • Blocked expansion valve/orifice tube
  • Clogged evaporator drain hose
  • Faulty A/C blower

A/C Service & Repair at Scott’s U-Save

If your air conditioning isn’t working as it should, trust the experts at Scott’s U-Save to bring back your nice cold air! No matter the issue, our ASE Certified technicians will pinpoint and repair the source of your problem. Give us a call or schedule online with one of our four locations today.

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