The relay
J20
controls the compressor
engagment circuit.
The relay is supplied by relay
R1
:
line controlled by the ignition INT/A, protected by fuse
F15
:
both are housed in the junction unit
B1
.
The supply for the relay
R1 comes from
the direct line of the maxifuse J/B1 of B5, whilst the coil is supplied
by the ignition-operated line (INT/A): this line also supplies switch unit
H80.
via fuse
B27
.
The relay
J20
coil is suppiled by
the line protected by fuse
B39 See E5050 DIESEL ENGINES ELECTRONIC MANAGEMENT
.
Pressing the button in group
H80
,
sends a signal to the climate control system control unit
M70
- pin B5 - ; this checks the conditions for engaging the compressor
and sends another signal to the 4 stage pressure switch
K10
at pin A13.
This, in turn, if the pressure in the circuit
is correct, does not interrupt the signal which reaches the engine
control unit
M10
(pin 60 of connector A).
Control unit
M10
uses its own internal
software to send a signal (from pin 18 of connector A) to activate
the compressor which energizes the relay
J20
.
The relay operates the solenoid valve, at
12 V, which switches on the air conditioning compressor
L20
.
The engagement of the compressor is also
controlled, in the same way as described above, by the switch
I65
for the 'MAX DEF' rapid demisting function.