Easy to understand guide on how automotive air conditioner systems work, this
information pertains to most vehicles.
An air conditioner or climate control panel is designed to operate the various
settings to improve occupant comfort, these controls may differ in appearance but
perform the same basic tasks.
When a command is given to prompt the air conditioner system to activate, an
electrical signal is sent to the engagement clutch coil or internal valve of the
Climate Control Panel
Refrigerant (134a) is then circulated throughout the system as it is compressed.
Once compressed, the 134a travels to the condenser where it is cooled and transformed
into a liquid state.
The low pressure port is connected to the low side of the evaporator, a serpentine
belt is used to utilize engine power to rotate the internal workings of the compressor.
High pressure ports are always smaller is size than low pressure ports. To replace
the compressor visit -
Once the compressed (heated gas state) refrigerant has left the compressor it
is transferred to the condenser via a high side hose were it is cooled and condensed
back into liquid form.
Some condensers are designed with a receiver dryer attached which acts as a refrigerant
cleaner/moisture remover. To recharge your air conditioner visit -
Recharge Your Air Conditioner
Air Conditioner Compressor
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
which releases the refrigerant as low pressure into the evaporator.
This release causes the liquid to turn into a gas inside of the evaporator core,
this expansion creates the absence of heat (coldness). The evaporator core is located
inside the passenger compartment or just outside the firewall. After completing
its journey through the evaporator, the refrigerant is returned to the compressor
via the low side hose where the cycle begins again. If your air conditioner is not
working visit -
Air Conditioner Troubleshooting
Air Conditioner Condenser (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 and onto the occupants
of the vehicle.
Evaporator Core (Heater Plenum Removed)
This diagram shows the system and refrigerant flow, these systems are closed
(sealed) which continuously re-circulates the refrigerant. After the system has
been repaired it must be vacuumed down and recharged visit -
Down and Recharge Your Air Conditioner
Hoses and components should be checked for deterioration, bubbles, cracks, hardening
or oily residue which could be signs of leakage. Visit -
Air Conditioner System
Proper refrigerant levels should always be maintained, low system
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 the condenser
in front of the radiator regularly.
(Note: An air conditioning system is under high pressure,
until the system is discharged completely, no repairs should be performed.
Eye protection should always be worn when working with an air conditioner.)
If further assistance is needed, our certified car repair technicians are ready
to answer car repair questions for free
Article first published 2016-02-02