How Does Your Car’s AC System Work?

It keeps us cool in the sweltering summer heat and it keeps our windshield from fogging up. Our vehicle’s air conditioning can make the difference between a comfortable ride and an unbearable one.

A car AC is made up of several different parts that each play an important role is keeping this system functioning properly.

Continue reading for a detailed answer to the question: how does car AC work?


Mounted directly behind the grill of your vehicle is the condenser. The condenser is responsible for reducing the temperature of refrigerant while still maintaining its high pressure. At this stage, the refrigerant changes from a gas to a liquid as it cools.


Driven by the serpentine belt, the condenser acts as the power unit of the AC system. It separates the low-pressure from the high-pressure side, compressing the low-pressure gas into high-temperature/pressure.


Between the condenser and metering device is the dryer. The dryer removes the water from refrigerant using a drying agent to avoid clogging the metering device. It also filters out other debris, like dirt, dust and metal particles, that might harm the system

Metering Device

Every car AC system has a metering device that controls how much refrigerant goes through the rest of the system. This device is usually either an expansion valve or fixed orifice tube that’s mounted on the high-pressure side of the system. This part of the process reduces pressure and rapidly cools the refrigerant.


The last part of the system is the evaporator, located behind the dashboard inside of your vehicle. At this stage, the refrigerant converts back to a gaseous state which causes a cooling effect. This is the cold air you feel through your air vents in your vehicle.

Common AC System Issues

Below are some common AC system issues that you may encounter. Keep in mind, most of these issue should be addressed by a professional.

Leaking refrigerant

A leak can occur at any part of the AC system, although they tend to happen around the hose connections.

Blocked/clogged condenser

A condenser can be blocked or clogged by some type of debris from the road, rendering it unable to properly cool the refrigerant. This will quickly cause the A/C unit to only expel hot air.

Electrical issues

By far the hardest issue to diagnose, electrical issues can be caused by broken or frayed wires.

Faulty cooling fans

When cooling fans aren’t functioning properly, the condenser isn’t being cooled down properly. The issue might be a piece of debris stuck in the fan, or be caused by faulty electrical.

Bad compressor

As the power unit to the AC system as a whole, when the compressor doesn’t work, the rest of the system can’t either. Oftentimes, when a compressor hasn’t been used in a long time, during winter, for example, a sudden start can shock the system. It’s recommended to periodically run your AC during the colder months to keep the compressor primed for the summer days ahead.

Trust the Professionals

Your vehicle’s AC system is a delicate, complex system that should be maintained and serviced by a professional. Scheduling regular checkups can avoid costly repairs down the road.


Got AC problems? Get in touch with the professionals at Telle Tire, and get back on the road quicker. Schedule an appointment today!