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 54 of connector A. According to its inner control
strategy, control unit M10 send a compressor activation command
from pin 29 of connector A which excites relay T5 so that the
electromagnet for activation of air conditioner compressor L20 is
controlled at 12 V.