Mechanics

Air Conditioner

Easy to understand guide on how an automotive air conditioner system works, this information pertains to most vehicles.

The air conditioner or climate control panel is designed to operate various settings while driving a motor vehicle, these controls may differ in appearance but basically perform the same tasks.


Climate Control Panel

When a command is given to prompt the air conditioner system to activate, an electrical charge is sent to the engagement coil of the compressor clutch, gas refrigerant is then circulated and compressed, once compressed it travels to the condenser which causes the refrigerant is transform into a liquid. (Note: Some compressor's are designed with an internal valve (instead of a clutch) which starts the flow.) A low pressure port is connected to the low side of the evaporator, and the high pressure port is connected to the condenser, a serpentine belt is used to power the compressor. (Note: High pressure ports are always smaller than lower pressure ports.)


Air Conditioner Compressor

Once the compressed (heated) refrigerant has left the compressor its transferred to the condenser using a hose were its cooled and condensed back into liquid form, but still under under high pressure. These units can also have a receiver dryer which acts as a refrigerant cleaner/moisture remover.


Air Conditioner Condenser (Removed)

After the compressed refrigerant is cooled by the condenser, it enters a high side hose in liquid form, which is attached to the expansion valve or orifice tube that releases the refrigerant into low pressure, this causes an expansion while the liquid turns into gas inside of the evaporator core, this expansion creates coldness. The evaporator core is located inside the passenger compartment or just outside of the firewall. After completing its journey through the evaporator, the refrigerant is returned to the compressor through the low side hose were the cycle begins again.


Evaporator Core (Heater Plenum Removed)

The climate control blower motor is used to push air through the evaporator core which delivers the cold air flow into the venting system.


Blower Motor

Basic automotive air conditioner system diagram and refrigerant flow chart, these systems are closed (sealed) which continuously re-circulate refrigerant.


Air Conditioner System

Helpful Information

Hoses and components should be checked for deterioration, bubbles, cracks and hardening or oily residue, all could be signs of leakage.


Leaking Condenser

Proper refrigerant levels should always be maintained, low system refrigerant charge is a common cause of a weak AC system. Odors can developed in the air conditioning system when a fungus has grown on the evaporator core, aerosol disinfectants can be used to remedy this condition. Refrigerant charging kits are available at many auto parts stores. Leaves and dust particles can get logged in the condenser hindering its performance, use a garden hose or compressed air to clean.

(Note: An air conditioning system is under pressure, until the system is discharged completely, no repairs or disassembly should be performed. Eye protection should always be worn.)

AUTHOR


Written by
Co-Founder and CEO of 2CarPros.com
35 years in the automotive repair field, ASE Master Technician, Advanced Electrical and Mechanical Theory.


COMMENTS TO THIS ARTICLE


Please use our question form if you have a specific question about your car as we are not able to give you a full answer on this page.



Article first published