3023546 - E6020 AIR CONDITIONING - Description

Description

The vehicle climate control system involves a duct/distributor unit with a heater. The air conditioning system includes the heater and has the function of producing cold, dehumidified air by switching on the compressor and the cooling system.

The climate control is operated by acting on the three knobs in the dashboard:

• the left knob controls mixing of hot and cold air;
• the right knob, mechanically operated via a cable, controls the opening of the flaps which regulate the distribution of air flows;
• the centre knob electrically controls the ventilation of the air at four different speeds;

The air recirculation button and the button for switching on the air conditioning compressor are located in the lower part of the control panel.

A dedicated control unit manages system operation by controlling:

• Air distribution to the vents.
• speed of the fan (varies continuously);
• activation of the compressor (air refrigeration circuit);
• activation of air recirculation;
• The MAX-DEF fast defrost function (i.e. a set of actions which allow both the windscreen and the rearscreen to be demisted quickly);

The control unit sets the above parameters in order to adjust passenger compartment temperature to the required level.According to the setting, the control unit adjusts passenger compartment air intake speed by means of the fan motor and air temperature by a mixer actuator. It also controls flow distribution via another actuator and - lastly - the interior/exterior air recirculation function via a final actuator. When required, the ECU automatically activates the cooling circuit and dehumidifies the air by operating the air conditioner compressor  See E6021  COMPRESSOR ENGAGEMENT . For more details  Characteristic of working principle 5040  AIR CONDITIONING CASING AND COMPONENTS .

Recirculation brings about closing of windows  See E3050  ELECTRIC FRONT WINDOWS and sun roof  See E3060  SUN ROOF . The air conditioning control unit downloads a signal from the gas presence sensor and activates the recirculation function to prevent polluted air from being taken into the passenger compartment. When normal conditions are restored, the climate control system ECU resets recirculation to the position prior to function activation. Because recirculation is activated under these conditions, a command is sent for automatic closure of the windows  See E3050  ELECTRIC FRONT WINDOWS and sun roof  See E3060  SUN ROOF .

The climate control system ECU receives a signal from the body computer to indicate that the windscreen washer is on and activates the recirculation function to prevent the liquid detergent smell from entering the passenger compartment.The vehicle speed signal - received by the CAN network - is used to filter outdoor temperature and adjust ventilation and the dynamic air intake according to car speed.The body computer continually downloads a battery voltage signal for comparison with its limit value. If the recorded battery voltage is lower than the threshold, the computer cuts in via the CAN network to send a signal to disable a series of appliances: this includes the fan control.The climate control system ECU is supplied by an ignition-operated line protected by a fuse in the underfacia control unit; the fan is supplied by a line protected by a specific engine bay control unit fuse.