Relay T5 of engine bay control unit
B1
controls the compressor activation circuit
The relay supply arrives from the line of
maxifuse CVM located on the battery, connector
B99
, via
the line of special fuse F19 of engine bay control unit
B1
.
The power supply to the coil of relay T5
arrives from main injection relay T9 and ignition-opeated line
(15/54) protected by fuse F18, both located in engine bay control
unit
B1 See E5050 DIESEL ENGINES ELECTRONIC
MANAGEMENT
.
Climate control system ECU
M70
sends
an enablement signal for compressor activation to 4-stage pressure
switch
K10
: if pressures in the coolant circuit are correct,
the signal emerges from the pressure switch and reaches engine control
ECU
M10
, pin 6 of connector A. According to its inner
control strategy, control unit
M10
send a compressor activation
command from pin 18 of connector A which excites relay T5 so that
the electromagnet for activation of air conditioner compressor
L20
is
controlled at 12 V.