Car Air Conditioning System Diagram - The Engineering Knowledge (2025)

Vehicles come with an air conditioning system to provide controlled temperature for passengers in high-temperature conditions. Some advanced vehicles have features to control temperature with the use of engine heat.

The air conditioning system of vehicles uses refrigerant gas and a compressor for air cooling in the cabin. The compressor has a connection with the evaporator that reduces the air temperature passing.

That cool air is distributed in the car cabin through vents. Here we will go over details for the car air conditioning system and its related diagram that helps to understand the works. Let’s get started with the introduction to the car air conditioning system.

What Is a Car Air Conditioning System?

• The air conditioning system of the car comes with different components that operate to cool the interior of the vehicle. Its wiring is like the AC used in our homes for cooling.
• This system does not directly produce low-temperature air but cools the environment of the car according to requirements. For this purpose, it uses some components like a compressor, a condenser, and an evaporator.
• In cars, two types of air conditioning systems come with an expansion valve system that reduces the pressure of refrigerant, and other types use an orifice tube.

Car Air Conditioning System Diagram

Here you can see a diagram of the car air conditioning system with connected components.

Car Air Conditioning Working

• The basic function of a car air conditioning system is to cool and remove heat from the air in the car cabin, as other AC systems do.
• The AC system of vehicles gets power through refrigerant gas and, with the use of a compressor, reduces the air temperature of the internal environment of the car.
• The compressor is connected to the evaporator, which cools the air moving.
• That low-temperature air then passes through the vent of the car cabin. If we turn off the car engine, the refrigerant gas does not move, and the car again gets a high temperature.
• 3 main components that control the working of the car air conditioning are
  • Compressor
  • Condenser
  • Evaporator

Components of a Car AC System

Different components of the car’s air conditioning system are used for cooling the interior of the car. These parts of the car air conditioning system are explained here.

Compressor

• The compressor is the main component of the air conditioning system. Its main function is refrigerant pressurization for cooling air, which detects temperature changes internally and externally of the car. It also regulates the temperature value and moves air towards the condenser.

Condenser

• In front of the radiator, the condenser of the AC system exists. It is also called a mini radiator since it has a design like a radiator.
• High-temperature gases that are released get cooled and compressed as a result of compressor pressure.
• The main function of the condenser is to shift cooled refrigerant to the receiver dryers.

Receiver, Dryer

• Based on the model, vehicles come with an accumulator. Receivers used in vehicles come with a thermal expansion valve and an accumulator used with an orifice tube. The receiver’s main working is to separate gases from liquids to prevent liquids from moving in the compressor. Compressor made for gas handling since liquids get contamination, but filter has purification features. Another working of the compressor is to remove moisture with the use of desiccant.

Thermal Expansion Valve

• The thermal expansion valve, also called the orifice tube, is connected between the condenser and evaporator. Thermal expansion valves operate with the use of receivers, and vehicles that have orifice plates operate with accumulators.
• The main working of a car air conditioning system is to control the pressure and temperature of the system.

Evaporator

• The evaporator exists behind the dashboard and uses refrigerant for cooling air before it moves to the cabin. This component moves refrigerant through a closed-loop system and then varies it from gas to liquid and makes it gas again.
• Car engines give power to compressors that transform low-pressure gas into high-pressure gas before moving to condensers for releasing heat and low-temperature gases.

How to Check Refrigerant Level and Recharge

Try to keep the AC system cool with the use of a refrigerant level that is monitored and controlled by professionals.

Evaporator & Condenser Cleaning

• Efficiency can be increased and unpleasant smells through proper cleaning of the evaporator and condenser of car AC service.

Cabin Air Filter Replacement

• Provide proper airflow and control cleaning air in the car through proper replacement of cabin air.

Compressor Inspection

• Accurate compressor inspection provides leak inspection and any damage to avoid damage and any costly repairs system.

Belt and Hose Inspection

• Do a proper inspection to find cracks and leaks in belts and hoses to avoid any damage and fulfill the requirements of the system.

Leak Detection

• Accurate detection and sealing of leaks also increases working performance.

Car Air Conditioning System Types

There are two basic types of car air conditioning systems. These are explained here.

Expansion Valve System

• In vehicle air conditioning systems, expansion valves are commonly used. It regulates refrigerant movement towards the evaporator through the expansion valve.
• Expansion valves retain refrigerant moving at a uniform speed that keeps the car’s inner temperature at normal conditions.

Benefits

• It provides good cooling efficiency with a longer working life of the compressor.
• It provides accurate temperature regulation.

Drawback

It is high cost as compared to a fixed orifice tube system and needs more maintenance. How to Check Refrigerant Level and Recharge

Try to keep the AC system cool with the use of a refrigerant level that is monitored and controlled by professionals.

Evaporator & Condenser Cleaning

• Efficiency can increase and control unpleasant smells through proper cleaning of the evaporator and condenser of car AC service.

Cabin Air Filter Replacement

• Provide proper airflow and control cleaning air in the car through proper replacement of cabin air.

Compressor Inspection

• Accurate compressor inspection provides leak inspection and any damage to avoid damage and any costly repair system.

Belt and Hose Inspection

• Do a proper inspection to find cracks and leaks in belts and hoses to avoid any damage and fulfill the requirements of the system.

Leak Detection

• Accurate detection and sealing of leaks also increases working performance.

Car Air Conditioning System Types

There are two basic types of car air conditioning systems. These are explained here.

Expansion Valve System

• In vehicle air conditioning systems, expansion valves are commonly used. It regulates refrigerant movement towards the evaporator through the expansion valve.
• Expansion valves retain refrigerant, moving at a uniform speed that keeps the car’s inner temperature at normal conditions.

Benefits

• It provides good cooling efficiency with a longer working life of the compressor.
• It provides accurate temperature regulation.

Drawback

• • It is high cost as compared to a fixed orifice tube system and needs more maintenance.

Fixed Orifice Tube System

• • The fixed orifice tube system is less complicated. It regulates the movement of refrigerant toward the evaporator with the use of a fixed orifice tube. Through limitation of refrigerant flow, a fixed tube provides a constant inner temperature.

Benefits

• It is a low-cost option compared to expansion valve techniques since it needs low maintenance.

Drawback

• It has low temperature regulation with reduced efficiency for the car.
• It has less compressor life.

Is the AC system in my car bad?

• If the air conditioning system of the car is not working well, then there are symptoms shown on the car that are signs of a bad AC system, which are listed here.

Weak Airflow

• Different reasons for weak airflow are shown over time during vehicle driving. These causes affect the AC system badly, and some main causes are.
  • The fried ventilation fan is a result of weak airflow. It occurs when the fan in the system is not blowing and affects airflow effectively.
  • It can be mold that accumulated in the evaporator core due to residual moisture.
  • The hose losses are the main causes of bad airflow for air conditioning systems.
  • There are also important causes that seals of blowers can open up. That affects airflow.

Bad A/C System Functionality

• The main reasons for these faults are
  • The lower motor is not working well, and if a clog exists, it expands the tube charging hose.
  • There can be some components, such as a fuse, a relay, or a solenoid, that can be damaged.
  • There is a vacuum leak that occurs, and also chances for damaged condensers.
  • The system also affected due to bad compressor clutch.

A/C cools, but warms shorter.

• There are many causes for the proper working of the system. Some are.
  • • A clogged expansion valve is the main issue for this error,, and a faulty compressor clutch also causes this problem.
  • • A fuse that gives power to the AC system can damage and affect the working of the system.

A/C Vents Smelling

• Here, in place of air from the vent, a bad smell is released, which is due to dirty cabin filters and an old evaporator.

FAQs:

At which point does car AC get air from?

• The recirculation AC mode recycles air existing in the car that pulling fresh air from the external area. That uses its air intake system that is on the front side of the car, normally at the base of the windshield.

Does the car AC system use fuel?

• Yes, it consumes fuel but has a very low amount. The AC compressor gets power from the engine which uses fuel for working. Some of the latest cars have effective systems and come with low fuel composition for cooling the car.

How to Troubleshoot My Car Air Conditioner?

• For troubleshooting air conditioning issues in a car, first of all, check fuses and relays, and also check the refrigerant level, and also check that the air intake is not clogged. If all these components are not working, get service from a professional.

What are the 5 main AC parts in a car?

• Compressor.
• Condenser.
• Thermal expansion valve
• Evaporator.
• Accumulator or receiver/drier.

Does car AC use fuel or battery?

• In some cars, the air conditioning system does not use fuel. The AC compressor is mechanically operated by the engine, so it uses the engine to work and uses more fuel. The more fuel is used, the lower it is, and it can be noted for short traveling.