Air Conditioner

General Information

1 — blower fan
2 — evaporator
3 — expansion valve
4 — low-pressure service port
5 — high-pressure service port
6 — receiver-drier
7 — condenser
8 — compressor
a — outside air for condenser cooling
b — heated air, discharged to the environment
c — uncooled air, supplied through the heater blower
d — cooled air, supplied to the cabin
A — high pressure (gas)
B — high pressure (liquid)
C — low pressure (liquid)
D — low pressure (gas)

With the air conditioner, the cabin air temperature can be lowered below the outside temperature. With a fully automatic system, the cabin is maintained at the set temperature. The air distribution and volume are regulated by the electronic module independently of vehicle speed. For this, electronic sensors transmit outside air and cabin air temperature information to the electronic module. Air dampers and the outside air blower are controlled by servo motors. Possible faults in the control unit, sensors and actuators are stored in the fault memory. The contents of the memory can be read using a special tool.

A/C System Operation

The A/C compressor is driven by the engine crankshaft through the V-belt. It compresses the A/C refrigerant to a pressure of 30 bar, which heats the refrigerant. In the condenser, the heated refrigerant is cooled by air flowing through it. As the refrigerant cools, it condenses into a liquid. Under high pressure, the liquid flows through the expansion valve. Due to the pressure drop, the liquid cools and evaporates. While flowing through the evaporator, the cooled refrigerant absorbs heat from the air blown through it. The air is cooled and enters the passenger compartment. The refrigerant, now a low-pressure gas, returns to the compressor.

* A/C system repair procedures are not described here. Repairs must be performed at a specialized service center. In particular, do not open the refrigerant circuit, as contact with the liquid may cause burns.