The relay
J20
controls the compressor
engagement circuit.
The relay receives a supply from the line
controlled by the ignition (INT/A) for the relay
R1
protected
by fuse
F15
: both are housed in the junction unit
B1
.
The coil receives a supply controlled by
the ignition (15/54) from the line from fuse
B25
up to 2/99
or from fuse
F4
of the additional fuse box
B98A
from
2/99; the relay is thus energized by an earth signal coming from
the engine management control unit
M10
: in this way the air
conditioning compressor L20 engagement electromagnet is operated
througha voltage of
12 V
.
Functional description
The engagement of the compressor
L20
is
also controlled by means of a special thermal contact
I60
which
intervenes if the temperature is too high.
Functional description
The climate control control unit
M70
(pin
7 of connector A) sends the signal for enabling the engagement of
the compressor to the 4 stage pressure switch
K10
; if the
pressures in the circuit are correct, the signal leaves the pressure switch
and reaches the engine control unit
M10
. (pin 3 of connector
B).
According to its own internal control logic,
the control unit
M10
sends the command to engage the compressor
(from pin 33 of connector D) which energizes the relay
J20
.