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Understanding automobile air conditioning system

Keeping the satisfaction of automobile engines at a high level, they are designed with an air conditioning system. This system works exactly like the air conditioner we use in our house and offices but cooling sources differ. The system allows the car interior to be cooled in hot weather providing a cooler environment for the users. Modern vehicles are cool that they are designed to control cold weather with the heat obtained from the engine. That is, the engine interior will be warm during cold weather. Well, this is a topic for another day. 

The air conditioning system was first properly introduced by the Packard Motor Company in the united states in 1939. The feature in the car at a time add to the purchase rate of their product. Today, the system is a common feature all vehicles must have as a convenience for humans is necessary. 

automobile air conditioning system

Today we’ll be looking at the definition, function, components, diagram, working principle, and symptoms and troubleshooting of bad automobile air conditioning systems. 

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What is an automobile air conditioning system?

A car air conditioning system is a set of components that function together to emit coolness to a car’s interior. As earlier mentioned, the automotive air conditioning system works much like the AC system we use at home and office. 

Most people think the air conditioning system creates cold air, that’s quite wrong. Well, if you are one of them you will see how it works. With the big change in automobiles, over 75 years ago, the air conditioning system still works with the same working principle. Its functional component includes a compressor, condenser, and evaporator. All these are further explained.

The primary function of an air conditioning system is to cool the surrounding to comfort the people around. With an air conditioning system, one gets cooler and comfortable when a scorching sun of summer prevails. So, the function of the air conditioning system remains the same. 

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Components of automobile air conditioning system

Below are the components of the air conditioning system in an automobile: 


The compressor is one of the major components in the air conditioning system. Its functions include pressurizing the refrigerant to cool the air, sensing temperature changes inside and outside the car, monitor and controlling temperature output, and finally, moving air to the condenser. 


The condenser in the car air conditioning system is located at the front of the radiator. It has been named a mini-radiator as it lookalike with the radiator. Its function is to reduce the temperature and pressure of hot gasses coming from the refrigerant as the compressor pressurizes the refrigerant. Another function of a condenser is to transfer cooled liquid refrigerant to the receiver/dryer or accumulator. 

Receiver/Dryer or Accumulator:

A vehicle can use either receiver or accumulator depending on its model. The receiver is used in vehicles that have a thermal expansion valve, while an accumulator is found in vehicles that use an orifice tube. 

The function of the receiver is to separate gas from liquid to avoid liquid from getting into the compressor. Compressors are designed to contain gas, liquid may cause contaminants, well some filters protect the system from contaminants. Compressors eliminate moisture with the help of a desiccant. The desiccants are like a small, bead-filled packet you find in packaging for new electronics. 

On the other hand, an accumulator controls and monitors the amount of refrigerant that goes into the evaporator. 

Thermal Expansion Valve or Orifice Tube:

The thermal expansion valve or orifice tube is located between the condenser and evaporator. The thermal expansion valve uses a receiver/dryer, while vehicles with orifice tubes utilize an accumulator. Their purpose in the car cooling system is to monitor the amount of pressure and temperature of the system. They also calculate the amount of refrigerant that can go into the evaporator with no harm. 


The evaporator is located right behind the dashboard as it takes charge of cooling the air with refrigerant before it is blown into the cabin of the vehicle. Working Principle

The working of an automobile air conditioning system is less complex and easy to understand. With the components explained, you’ll be familiar with the most term used and their functions. The parts work hand in hand circulating a substance known as refrigerant through a high pressure or low-pressure closed-loop system. 

The refrigerant that causes the coolness changes from a gas to a liquid, and then back to gas. The process is the most vital stage in the cooling process. The compressor is driven by a belt powered by the car engine. This causes the low-pressure refrigerant gas to be compressed into a high-pressure. High-temperature gas is then sent to the condenser.  

The condenser looks like the car radiator, it helps to dissipate heat and also cool the high-pressure refrigerant gas. With this, the gas change into a high-pressure liquid. The high-pressure liquid removes all water in it using a dryer. It’s then pumped to the thermal expansion valve. 

In the design of an air conditioning system, the high-pressure liquid expands and becomes a low-pressure liquid. It enters into the low-pressure side of the loop system before it goes to the evaporator. The evaporator is located within the car interior.

Again, the low-pressure refrigerant liquid turns into a gas and passes the evaporator to take the heat from the interior of the vehicle. During the process, there is a fan that blows over the exterior of the compressor. It blows cool air into the interior of the vehicle. The low-pressure refrigerant gas enters the compressor again for the process to happen.

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Signs or Symptoms of Bad or Failing Automobile Air Conditioning System

Below are the symptoms and causes of an automobile air conditioning system: 

Weak Airflow:

Overtime drivers experience weak airflow in their car, which is caused by a lot of factors. This symptom that could damage or cause fatal damage to the A/C system. Below are the causes of weak airflow: 

  • A fried ventilation fan is a cause of weak airflow. This is when the fan in the system is not blowing causing air not to flow effectively. 
  • There could be mold accumulated in the evaporator core from residual moisture. This prevents the air from reaching the air vents. 
  • Weak airflow in the car air conditioning system is caused when the hose lose. This hose supplies air to the blower unit, so when it gets loose airflow is obstructed. 
  • The core case that houses the blower have seals that can open up. This also will diminish the airflow of the system. When this happens, the whole system is compromised. 

The functionality of the A/C system is reduced:

You’re A/C will sometime lack precious coolness, which could be caused by several reasons. When the symptom occurs, it should be fixed as soon as possible else big damage will be caused to the system. Below are the causes of these symptoms. 

  • A failed blower motor or blower resistor.
  • If the tube or refrigerant charging hose is expanded by a clog.
  • When the electrical parts like a fuse, switch, relay, solenoid, or control module fail, the symptoms occur. 
  • A damaged or failing condenser or evaporator is also the major cause. 
  • Leak vacuum 
  • A failed compressor or compressor clutch can also cause a weak system. 
  • Freon leak is caused by a failed o-ring seal or component. 

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A/C system cool at first and then get warm in no time:

This is caused by the various issue, but you should it inspect and fix to keep the system normal. A DIYer won’t be able to fix the issue else the whole system will be scattered. Below are the common causes of such a problem: 

  • A clogged expansion valve is a major cause of this problem. The expansion valve supplies the proper amount of refrigerant to the evaporator. If the valve is blocked, the refrigerant won’t be able to flow into the evaporator. A clogged valve and also if moisture is present, the refrigerant begins to freeze. 
  • A faulty compressor clutch is also a major cause of such an issue. The faulty clutch won’t able to engage with the compressor, which will cause the compressor not to maintain the correct pressure. it will then result in hot air. 
  • The fuse that powers the A/C system can shoot out and cause the system to stop working. 

Receiving gym locker odor from the A/C vent:

Instead of experiencing cool air from the vent, the order from the gym locker take charge, which is not cool. Below are the common causes of the issue: 

  • A moldy evaporator case is a common cause.
  • It can also be caused by dirty and old air cabin filter. 

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In conclusion, we saw the various aspect of the automobile air conditioning system in detail. We’ve given the definition, function, components, diagram, working principle, and symptoms of a bad and failing system. 

I hope you enjoyed the reading, if so, kindly comment, share, and recommend this site to other technical students. Thanks! 


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