3239479 - E6020 AIR CONDITIONING - Functional description
Functional description
The climate control unit
M70
receives a supply controlled
by the ignition (INT/A) at pin 5 of connector B from the line protected
by fuse
B10
up to 2/99 or fuse
F6
of the additional
fuse box
B98B
from 2/99.; the same line also supplies all
the actuators of the system.
The direct supply arrives from the battery
(maxifuse
J/B1
of
B5
up to 2/99 or
B99
from
2/99) at pin 10 of connector B through fuse
F10
of junction
unit
B1
.
The supply for illuminating the controls
with the side lights on reaches pin 2 of connector B from the line
coming from the switch for the steering column switch unit
H5
protected
by fuse
B11
up to 2/99 or fuse
F4
of the additional fuse
box
B98B
from 2/99.
Pin 14 of connector A of
M70
is earthed.
Pin 7 of connector B of
M70
receives
the speedometer signal coming from instrument
E10
, whilst
the outside temperature value is signalled from pin 1 of connector
A also at instrument
E10
.
The sensor which measures the outside temperature
is located on the right external rear view mirror
P61
: the
sensor receives a 5 V supply from pin 13 of connector A of
M70
and
sends the signal to pin 10 of connector A.
Control unit
M70
is also connected
to sensors
K87
(lower treated air),
K88
(upper treated
air) and
K89
(passenger compartment air), which receive a
5 V supply from pin 13 of the connector and send signals to pins
11, 10, 9 respectively of connector A of
M70
.
Sensor
K89
is fitted with a fan motor
controlled by the ignition so that the temperature reading is not
affected by the motionless and thus warmer air inside the dashboard.
Functional description
The air conditioning system is
equipped with three activators for recirculation (
N82
), air
mixing (
N81
) and air distribution (
N80
).
The recirculation actuator
N82
is
controlled by the control unit
M70
from pin 11 of connector
B, and there is a current feedback at pin 3 of connector A of
M70
.
The mixing actuator
N81
is controlled
by the control unit
M70
from pin 6 of connector B, receiving
a supply for controlling the potentiometer from pin 2 of connector
A and sending a feedback signal to pin 12 of connector B.
The distribution actuator
N80
is
controlled by the control unit
M70
from pin 16 of connector
A, receiving a supply for controlling the potentiometer from pin 2
of connector A and sending a feedback signal to pin 9 of connector
B.
The electronic governor
M72
operates
the fan at different speeds: it receives an input signal from the
control unit (from pin 3 of connector B) and transforms it into
a variable voltage signal that controls the fan. This voltage control
is also stabilized, i.e. it is independent of the battery voltage
variations. The governor supply is controlled by the ignition (INT/A)
from fuse
B10
up to 2/99 or fuse
F6
of the additional
fuse box
B98B
from 2/99, is connected to earth and also sends
the temperature control signal to pin 4 of connector A of
M70
.
The fan
N85
is supplied directly
from the battery through the A/C maxifuse line of
B6
, whilst
it is controlled at the different speeds for the voltage signal coming
from the electronic governor
M72
.
The control unit
M70
is equipped
with a self-test system which can be used by connecting the unit
to connector
R10
: it receives signals from pin 8 of connector
B through the diagnostic line.
The commands for switching on the heated
rear windscreen, the LED and the "rapid demist" function
are transmitted to the integrated services control unit
M40
by
pin 1 of connector B and pins 6 and 8 of connector A, respectively.
It should be remembered that the climate control control unit only
"houses" the control button and the LED, but does not
in any way affect the heated rear windscreen activation logic. (
See E3030 HEATED REAR WINDSCREEN AND DOOR MIRROR DEFROSTING
.)
Pin 7 of connector A controls the activation
of the compressor (
See E6021 COMPRESSOR ENGAGEMENT
).