Lotus 2004 Eleven Service Notes page 446

Lotus Service Notes
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:
INTERIOR CLIMATE CONTROLS
Temperature Fan Speed
Air conditioning
(if fitted)
Section PL
p98b
Distribution
Re-circulation
(if fitted)
p99
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