The main components of the AC system are the compressor, condenser, expansion valve and evaporator, as well as the refrigerant used to absorb the heat, which in most existing systems, is known as R134a.Checked 2026-08-16
Air conditioning system components
The compressor, condenser, expansion valve and evaporator that move heat out of the cabin.
Also called: A/C compressor · condenser · expansion valve · evaporator
What it means
Definition
A vehicle air-conditioning system moves refrigerant through four main components. The compressor circulates and pressurizes it; the condenser releases heat outside the cabin; the expansion valve drops its pressure; and the evaporator absorbs heat from cabin air before the blower sends that cooled air through the vents.
Why a buyer cares
What it changes
An estimate that says only ‘A/C repair’ is incomplete. Naming the failed component separates a refrigerant leak, an airflow problem and a compressor fault — three repairs with very different scope.
In practice
Where you meet it
On A/C inspection reports and estimates, usually beside a refrigerant type and a leak-test result.
Two things that look alike
Not the same as
The blower moves cabin air; the compressor moves refrigerant. One can work while the other does not.
Read next
Related terms
Where this comes from
Sources
The physical layout and control strategy vary by vehicle, especially in hybrids and electric vehicles.