The relay
J20
controls the compressor
engagement 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 line .(INT/A) protected by the
fuse
B26
.
The relay
J20
coil is always supplied
by the line controlled by the ignition (INT/A) protected by fuse
B27
:
this line also supplies the switch unit
H80
.
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, at pin A13, to the 3 stage pressure switch
K5
.
This, in turn, if the pressure in the circuit
is correct, does not interrupt the signal which reaches the engine
control unit
M10
.
Control unit
M10
uses its own internal
software to send an (earth) signal 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 switch
I65
for the 'MAX DEF' rapid demisting function.