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 is supplied by the line from fuse
F2
of
the additional fuse box
B98 A
, of the main injection relay
J10
;
the relay is energized by an earth signal coming from the engine
management control unit
M10
: in this way the air conditioning compressor
engagement electro-magnet
L20
is operated through a voltage
of 12 V.
Climate control unit
M70
( pin 7
of connector A) sends a compressor enablement signal to four-stage
pressure switch
K10
. If circuit pressures are correct, the
signal leaves the pressure switch and reaches engine control unit
M10
- pin
6 of connector A. According to its internal control logic, the control
unit
M10
sends - from pin 13 of connector A - the command
to engage the compressor which energizes the relay
J20
.