2401096 - Introduction - CLIMATE CONTROL - MISCELLANEOUS

This vehicle is equipped with two passenger compartment climate control systems:

  • manual climate control
  • dual zone climate control system
The climate control system allows the properties of air taken into the passenger compartment (temperature, humidity) to be changed.

The difference between both system types, i.e. manual and automatic, lies solely in the way the system is managed:

  • manual climate control: the user adjusts certain air temperature, distribution and flow settings. These remain the same until they are re-adjusted by the user
  • automatic climate control system: the user can set parameters and instruct the system to manage them automatically. The user retains the ability to manage the system, if required.
The automatic climate control system fitted to this vehicle is dual zone (driver zone and front passenger zone), i.e. the system is equipped with dual controls for the driver and passenger. It is able to manage the settings of both users by altering air temperature and distribution (flow rate cannot be adjusted differently for both areas) with a certain degree of independence. The figure below depicts the manual climate control system
1 Air mixer control wheel 2 Air speed selection knob 3 Passenger compartment air distribution selection wheel 4 Recirculation selection knob 5, Rear window demister activation key 6, Compressor activation key Both main controls are coaxial rotor type, i.e. they consist of an outer rotating wheel and an internal knob that allows two different settings.

Operating strategy

The manual air condition allows the user to manage passenger compartment air temperature and intake by mean of the control wheels and knobs.

The following parameters/functions can be modified manually:

  • Temperature
  • Distribution pattern to 5 settings
  • Fan speed.
  • Compressor enabled
  • Demist/defrost function.
  • Recirculation.
Air mixing, distribution and circulation commands are directed from the knobs to the climate control system casing via flexible cables (bowden cables).To prevent the evaporator from freezing if the compressor is activated with zero passenger compartment air fan speed, the fan is operated automatically at the first speed.The enablement supplied by the demisting sensor constitutes another limitation. This sensor detects ice formation on the evaparator and thus disables the compressor to prevent the evaporator from freezing. This system may be managed automatically by an electronic control unit known as the 'Climate Control System Node' (NCL) that is responsible for maintaining climate control system settings entered by the user (or users) unchanged.The NCL is connected to the B-CAN network of the vehicle electrical system.The NCL is built into the climate control system panel installed in the middle of the instrument facia.The following figure depicts the back of the control unit showing connections to the electrical system and then the connector pin out.
40 pin connector
PINOPERATION
01CAN L line
02CAN H line
03N.C.
04Heated rear windscreen operation
05Fan control
06N.C.
07Solar radiation sensor supply
08Frost sensor
09Right VENT treated air temperature sensor
10Left solar radiation sensor
11.Analogue earth
12.Open recirculation control
13Heated rear window led
14Hazard warning light led
15Hazard warning light control
16Misting sensor
17Left FLOOR treated air temperature sensor
18Left VENT treated air temperature sensor
19Right solar radiation sensor
20Right FLOOR reated air temperature esnsor
21Compressor control
22Closed recirculation control
23N.C.
24Right mixer actuator shared
25Left mixer actuator feedback
26Right mixer actuator feedback
27Right distribution actuator feedback
28Left distribution actuator feedback
29Fan feedback
30Battery power supply
31External 5v supply
32Left mixer actuator control
33Right distribution actuator shared
34Right distribution actuator control
35Right mixer actuator control
36Left distribution actuator control
37Left mixer actuator shared
38Left distribution actuator shared
39Signal + key
40Electronic earth
If the control unit or one of the actuators are replaced, the flap positions must be initialised using an Examiner.

Operating strategy

The following figure depicts the front of the control panel:
1, Driver AUTOmatic mode key 2, Passenger AUTOmatic mode key 3, Wheel for modulating driver side temperature 4, Wheel for modulating passenge side temperature 5, Driver side air distribution selection keys 6, Passenger side air distribution selection keys 7, Display 8, Air flow adjustment keys 9, MONO zone mode selection key 10, Compressor activation key 11, Recirculation key 12, Control unit OFF key 13, MAX DEF key 14, Rear window defrost on key 15, Passenger compartment air temperature sensor 16, Hazard key

Operating strategy

The management control unit is capable of producing and maintaining the desired comfort in two areas of the passenger compartment by controlling the following parameters and functions:

  • Air temperature at the driver/passenger vents;
  • Speed of the fan (varies continuously);
  • Air distribution;
  • Compressor engagement;
  • Recirculation;

The following parameters/functions can be modified manually:

  • Driver/passenger side temperature
  • Fan speed.
  • Distribution pattern via 5 positions (driver/passenger side)
  • Compressor.
  • Demist/defrost function.
  • Recirculation.
Manual selections always take precedence over automatic selections and are stored until the user deliberately cancels the command, allowing the automatic device to take control over the relevant function.The manual setting of a function does not adversely affect the control of other functions set to automatic, in particular, the control of the temperature is always automatic when the system is running.All the buttons have dual functions (ON/OFF) including the recirculation The function is enabled after the button is pressed.The pressing of a button is only recognized after the previous button has been released.

Operating status display

Climate control system operating status is shown through LEDS and DISPLAYS.

  • RECIRCULATION function: key with car outline and amber led indicates recirculation function on when lit A symbol on the display also showing the car and an arrow indicating recirculation status;
  • Compresor Enablement Function led: key with snowflake symbol and amber led and logo on display indicating Compressor status.
  • AUTO/FULL AUTO ( messages on driver and passenger side displays): indicate that all functions are managed, zone by zone, by the control system. The FULL icon goes out if there is at least one manual Flow rate, Distribution, Compressor or Recirculation command. The FULL AUTO icon (or the AUTO icon if FULL is already off) goes out if the system is not capable, due to specific manual operations, of guaranteeing the required temperature for the zone being reached/maintained.
  • MAX DEF function LED: key with amber led, indicates MAX DEF function on, when lit.
  • HEATED REAR WINDOW LED: YELLOW, indicates heated rear window on.
  • Function led OFF: key with OFF wording and amber colour, indicates control off status when lit.
  • Distribution status led: amber, indicates passenger compartment air distribution status.
  • DISPLAY: NEGATIVE TRANSFLECTIVE type displays passenger compartment fan air flow, temperature settings in both passenger compartment zones (E1 and E2) by means of bars, compressor status (I), recirculation status (F), AUTO system management mode, FULL AUTO (A1, A2).

Comes on after car stops.

When the system is switched on the various parameters are checked manually or automatically depending on the selections made by the user before it was switched off.All the manual interventions made before the engine was switched off are stored in the memory until the next time the engine is started up.This also applies to the OFF function; if the system was OFF before shut-down, the system will again be OFF upon start-up.If at the previous key off the Max Def function was on, then at the key on the condition memorized before the Max Def condition is implemented.

Selecting a temperature setting

The passenger compartment temperature is set by the control unit each time the battery is connected at 22 °C. The user can modify the temperature setting by means of the appropriate keys.Changes take place in 0.5 ºC stepsThe temperature adjustment range is between 16 and 32 ºC; below 16. °C the value set becomes 'LO' whilst above 32. °C the value set becomes 'HI',When the control unit is switched off, the temperature setting, shown on the display, is stored in the memory and renewed at the next key on.

Winter starting transition

In order not to create problems that could disturb the user, such as cold air jets and/or front window misting, the system must activate a 'TRANSITORY START-UP PERIOD' management procedure when the control unit is activated under certain temperature conditions.

The control unit ensures that the following conditions occur simultaneously:

  • engine coolant temperature below -4° C
  • outside temperature below 19° C

When these conditions persist, the control unit implements the 'winter starting transitory' procedure and sets:

  • air flow rate to the first bar
  • distribution to DEF
  • mixing to AUTO conditions
During winter start-up transitory conditions, it is possible to automatically engage the compressor to dehumidify the air.The winter transitory procedure is turned off if outdoor temperature exceeds 21 °C the or coolant temperature raches 50 °C.All manual functions stored at the last key off are restored at the end of the winter transitory period.

LO condition

Maximum air cooling is achieved by setting a temperature below 16°C.

This user request involves the following actions:

  • Mixer: the air mixer flap is controlled in FULL COLD position
  • Distribution: the distribution flap is positioned (by default) on VENT and the led comes on (visible to the user)
  • Ventilation: the air flow is displayed as 12 bars
  • Recirculation: remains as set by the user with all the set recirculation rules
  • Compressor: enabled (led on if previously off).
Under LO conditions, all manual settings are accepted: a user request takes priority over the automatic control conditions imposed by the system in LO status.

Max cooling status management function is interrupted by one of the following functions that is given priority over max cooling management (LO)

  • +KEY OFF status management function;
  • OFF status management function;
  • MAX DEF status management function.

HI condition

Maximum air heating, is reached by setting a temperature above 32°C.

This user request involves the following actions:

  • Mixer: the air mixer flap is controlled in the FULL HEAT position
  • Distribution: the distribution flap is positioned to FLOOR and the led lights up on the control panel.
  • Ventilation: air flow is displayed as 12 bars (with limitations due to winter transitory conditions)
  • Recirculation: remains as set by user.
  • Compressor: remains as set by user.
Under HI conditions, all manual settings are accepted: a user request takes priority over the automatic settings imposed by the control system in HI status.

Max cooling management is interrupted due to one of the following functions being given priority over max cooling status (HI);

  • +KEY OFF status management function;
  • OFF status management function;
  • MAX DEF status management function.

AUTO function

When the AUTO key is pressed and the led comes on, control of the following functions is restored to the automatic device:

  • Air distribution
  • Fan speed
  • Compressor.
  • Recirculation.

Therefore, if external T >= 5 (C:

  • FULL AUTO logo ON;
  • compressor led comes on (i.e. activation request to engine management control unit) and snowflake symbol lit
  • AQS logo on (with flap in position set by prg. 2.9).

If outside T <= 3 (C:

  • FULL AUTO logo ON;
  • compressor led on (with compressor physically deactivated due to external temperature) and snowflake led off).
  • forced recirculation open (temporary dynamic regulation).

Specific situations:

  • the FULL led goes off when at least one manual distribitution, flow, recirculation and compressor setting is peformed.
  • When a manual adjustment is made to distribution/flow/compressor, recirculation, the system automatically returns to AUTO if the AUTO key is pressed
  • If the compressor is also switched off (ice LED and symbol off) then the system may not be capable of controlling/maintaining the temperature set. The user is notified of this situation by the snowflake symbol and the temperature set on the Clima display flashing.
  • If the compressor has not been enabled at the end of the flashing, the message FULL and AUTO disppears (or only AUTO if FULL was already off), the flashing compressor symbol disappears and the temperatures stop flashing.

Difference between FULL AUTO and AUTO modes:

  • FULL AUTO mode: the system manages all climate control parameters automatically (temperature, air speed and distribution)
  • AUTO mode: the system manages only temperature automatically and allows the user to adjust air speed and distribution manually.

Checking fan speed and display.

Air flow can be adjusted manually to 12 levels. These are displayed on a 12 bar display.If no manual operations are performed, fan speed is controlled continuously by the automatic device and indicated on the display by activation of the relevant number of bars for the flow rate.If the user operates the ventilation control manually, the system leaves AUTO status.Adjust the relevant keys to increase or decrease fan speed.When one of the two keys (up/down) is held down for longer than 0.8 seconds, the repeat function is activated, which increases air flow by one step every 0.4 seconds.If the compressor is disabled, the ventilation control can be adjusted manually until the display shows 0 bars, i.e. flow rate zero.If the compressor is enabled and the engine is started up, the manual ventilation cannot go below 1 bar (minimum flow rate) shown on the display, because, with the compressor enabled, there must be a minimum air flow rate to prevent the evaporator from freezing.

Air distribution control

There are 5 air distribution positions (VENT, BILEVEL, HEAT , FLOOR and DEF.In addition to the distribution control the system also displays the selection by lighting up the LEDs in the control buttons.Setting distributionOne of the 5 positions can be selected manually by operating the appropriate buttons in accordance with the following combination strategy.

Manual distribution is managed in three groups:

  • Main distribution: DEF (windscreen), VENT (front), FLOOR (footwells)
  • Comination distribution patterns: BI_LEVEL, FLOOR_DEF
  • Prohibited distribution patterns: all OFF, DEF-VENT, DEF-VENT-FLOOR

With the main distribution activated (one LED on) the following takes place when the same button is pressed:

  • the distribution remains unchanged;
  • the system switches to manual operation
When a key is pressed that generates the prohibited 'all OFF' distribution pattern or when 2 or 3 keys are pressed simultaneously, the distribution is not altered at the moment the key is pressed but remains unchanged.

Compressor management

Compressor managementThe compresor activation key is dual type and fitted with led lights. Press the key to enable the compressor control, activate the led and make the snowflake logo appear on the display.The compressor key led indicates whether the compressor activation request has been forwarded to the Engine Management Node. If the led comes on, the request has been forwarded.From now on, provided external temperature requirements are met, the system generates the amount of cooling required to control the climate inside the passenger compartment and the evaporator dehumidifies the air. These functional states are maintained even after successive KEYS OFF/ON.

Outdoor temperature also limits compressor operation in certain ways:

  • if Text <= 3°C the compressor is disabled
  • if Text = 5°C the compressor is enabled
  • if demising sensor enablement is present
- If temperature is between 3 and 5°C at KEY ON, the compressor is enabled.

Temperature setting flasher strategy

When the user disables the compressor, the following takes place:

  • the led on the key goes off and the symbol on the display disappears.
  • the FULL logo disappears from the display (if it was present before)
  • the control unit assesses whether the system is able to reach the set temperature with the current outside temperature. If so, the system operates normally and is able to provide the required service even without the compressor activated. If not, the systemis not able to supply the required service and indicates this by causing the temperature setting to flash.
If the compressor is not enabled when the temperature stops flashing, the AUTO message disappears until the Compressor is re-enabled.If the compressor is not enabled, the temperature flashing cycle begins again at the next key on/disablement of OFF.The Auto message reappears only once the Compressor has been re-enabled by the relevant key.The flashing system is not reinitialised until the AUTO logo has reappeared.IfText<=3°C, flashing and its consequences do not take place.The system turns on the compressor symbol as soon as Text>=5°C.

Recirculation key

The recirculation key employs a dual strategy.

This strategy allows three possible operating modes to be set:

  • Automatic recirculation (managed in accordance with certain specific rules defined below)
  • Recirculation bypassed to closed (passenger compartment air ( RFC)
  • Recirculation bypassed to open (outdoor air) (RFA)
The key (with led) showing a car outline is used to display various recirculation operating modes (if led is on, recirculation is BYPASSED TO CLOSED).When the control unit is turned off, recirculation is bypassed to closed;

Automatic recirculation

Recirculation is managed automatically (flap open/closed) taking into account the following rules, shown in order of decreasing priority):

  • air exchange rule: after 25 minutes of closed recirculation, the system opens the system for one minute to allow air inside the passenger compartment to be exchanged. Once this time has elapsed, the system returns to the conditions prior to opening.
  • temporary dynamic rule: when the user disables the compressor manually or when the compressor is turned off automatically due to low outdoor temperature, the control unit opens recirculation to prevent the inside of the passenger compartment windows from misting and and thus worsening the visibility.
  • transitory heat regulation rule to promote passenger compartment heating: during passenger compartment cooling, the system opens or closes recirculation on the basis of outdoor temperature. It always takes in air from the coldest point to speed up passenger compartment cooling.
Automatic recirculation mode is not displayed to the user by a message on the display or by means of leds.

Manual recirculation

Recirculation bypassed to closed: this type of manual operation is indicated by the led on the recirculation key coming on and indicates recirculation flap closure.Recirculation bypassed to open: this type of manual operation is indicated by the led on the recirculation key going off and indicates recirculation flap opening.

In this mode, the following rules are applied:

  • air exchange rule
  • temporary dynamic rule

MAX DEF

The MAX Def function (MAXimum DEFrost) is a set procedure activated by the relevant key.

This procedure involves activation of the following operations:

  • activation of led in Def air distribution position
  • storing of operational status and displays prior to the MAX DEF command
  • deactivation of led/messages relating to AUTO and recirculation functions
  • activation of DEF distribution, Compressor enablement, Recirculation open and heated rear window leds
  • indication of high temperature (HI) on display
  • indication of ventilation on display

If the MAX DEF function is activated after the winter start-up transitory, the following occurs:

  • air flow at 80% of maximum.
  • MAX DEF timer set to three minutes

If the MAX DEF function is activated during the winter start-up transitory period, the following occur:

  • flow remains as transitory flow, if coolant temperature is less than 35° C;
  • flow is 80% of maximum flow if coolant temperature reaches/exceeds 35° C;
  • the system waits for coolant temperature to reach/exceed 50° C to begin the 3 minute MAX DEF timer.
  • distribution flap set to Def
  • mixer flaps set to High Temperature
  • recirculation flap bypassed to open
  • compressor function enabled
  • rear window demister function enabled

During operation in MAX DEF mode, the following operations are possible without exiting from the procedure:

  • alter the air flow rate (increase/decrease) at will
  • deactivate the heated rear windscreen
The MAX DEF function is supended when any one of the climate control unit keys/commands is operated (recirculation/compressor enablement, auto, off, Max. Def, temperature and distribution)causing the system to return to the status prior to Max Def, except for the command associated with the pressed key, which must be implemented.Management of the MAX DEF procedure takes priority over the LO procedure (max cooling) and HI procedure (max. heating). If these are operating, operation is suspended if the MAX DEF procedure is activated.

Control unit/system deactivation

The following actions take place when the OFF key is pressed:

  • current status is stored
  • air recirculation bypassed to closed and led comes on
  • OFF led comes on and all other icons go off
  • compressor deactivated
  • fan deactivated
  • mixer set to max cooling
  • distribution set to Vent
When Off, the recirculation key can still be operated in dual (ON/OFF) mode without the automatic device.When OFF, the system comes back on when any key is pressed (except recirculation and Temperature) and all the operating modes previously stored by the system are restored.The air flow increase rocker switch restores all conditions prior to deactivation and simultaneously implements a manual flow request.If the system is turned back on with a Distribution key, only the main distribution requested is implemented.With the control unit OFF, it comes back on next time OFF is pressed. All conditions prior to deactivation are restored.