Lotus Elise / Lotus Exige. Manual - part 98

    

Lotus Service Notes                                 Section PL

Page 6

Airflow through a.c./heater unit

Cold air

Trunking to
distribution unit

Ambient or re-circulated
air inlet

      p110b

Heater

Fan blower

matrix

a.c. evaporator (if fitted)

Warm air

Flap in full
warm position

      p110a

Butterfly flap open

    

Lotus Service Notes                                 Section PL

Page 7

Interior Climate Controls

The interior climate controls consist of

two push switches (if fitted) for air condition-
ing and air re-circulation, and three rotary con-
trols for heater temperature, fan speed, and
air distribution.

Air Conditioning (if fitted)

The left hand push button switch requests

air conditioning, but the engine must be run-
ning and a fan speed selected before the sys-
tem will operate.  The a.c. switch receives its
feed from the fan speed switch and energises
the a.c. request relay.  When closed, the re-
quest relay supplies, via the a.c. thermostat
and trinary switch, an ECM input.  The ECM
processes a valid request input, and if other
parameters allow (e.g. not wide open throttle,
not excessive coolant temperature), the ECM
will open the IAC valve before energising the
a.c. clutch relay. Note also that ambient air
temperature must be above 3°C.

With a fully cold temperature setting,

refrigerated air will be supplied.  For dehu-
midified air, select air conditioning in conjunc-
tion with a warm temperature setting.

The tell tale in the switch button lights

up green when the circuit is active.

Air Re-circulation (with a.c.)

Air supply for the interior climate system is normally drawn from both the intake duct ahead of the engine

cooling radiator, and the vehicle interior.  When the re-circulation button is pressed, a stepper motor is acti-
vated to close a butterfly flap in the fresh air intake, in order to provide a 90% recirculation supply to the blower
fan.  The re-circulation facility should be used when maximum refrigeration is desired.  The tell tale in the
switch button lights up green when the circuit is active.

Heater Temperature

With the left hand rotary electrical control turned fully counterclockwise, the air blender flaps are posi-

tioned to direct all the airflow to by-pass the heater chamber so that no air heating is provided.  If air cooling is
required, use this temperature position in conjunction with air conditioning.  Turning the control progressively
clockwise operates the stepper motor attached to the upper flap spindle, and via toothed belt to the lower flap,
to direct airflow through the heater matrix and provide an increasing level of air heating until at the fully
clockwise position, maximum heat is supplied.

Fan Speed

The centre rotary switch provides three fan speeds to boost air circulation.  Turned fully counterclockwise,

the fan is off;  Turning the switch progressively clockwise operates the blower fan at increasing speed in three
steps.  Note that the fan operates only with the ignition switched on.  The fan speed resistors are mounted in the
top of the evaporator housing.

Air Distribution

The right hand electrical rotary control operates a stepper motor on the air distribution unit to direct airflow

to the windscreen, face level and footwell vents.  The following diagrams indicate airflow for the different
control positions:

   

 p99

Temperature

Fan Speed

Distribution

Air conditioning

Re-circulation

(if fitted)

(if fitted)

   

INTERIOR CLIMATE CONTROLS

    

p98b

    

Lotus Service Notes                                 Section PL

Page 8

Face Level):

Turned fully counterclockwise, the step-

per motor on the air distribution unit (ADU)
operates the rotary flap to close off the wind-
screen vents, and direct all airflow to the four
face level vents, each of which may be ma-
nipulated to adjust volume and direction.  The
footwell flap is closed.

Windscreen

Scuttle
baffle
panel

To face
level

Air distribution unit

vents

    From

Chassis scuttle

   climate
   chamber

Rotary flap

Connecting link

      p102a

Footwell flap closed

    

Lotus Service Notes                                 Section PL

Page 9

Footwell:

As the control is turned clockwise from

the face level vents symbol towards the
footwell symbol, the stepper motor turns the
rotary flap to progressively close off the face
level vents.  A rod connecting the rotary flap
to the footwell flap is arranged to open the
footwell vents in opposite proportion, until at
the footwell symbol, all airflow is directed to
the footwells.

.

Footwell flap open

    From
   climate
   chamber

Screen & footwell
ports closed off

To footwells

      p102b