192004786 - E6021 COMPRESSOR ENGAGEMENT - FUNCTIONAL DESCRIPTION

Functional description

Relay T5 of engine bay control unit B1 controls the compressor activation circuitThe relay power supply passes through the line of dedicated fuse F19 of engine bay junction 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.

Functional description

The climate control unit M70 sends an enablement signal for compressor activation to engine control unit M10, pin 6 of connector A.

Functional description

Pressing the button in group H80, sends two signals:

• to the engine control unit M10, at pin 6 of connector A;
• The second signal energizes the relay J34 coil which activates the first speed for the fan N85 , according to the description    See E6020 AIR CONDITIONING.

Fan N85- supplied by ignition-operated line (INT/A) of relay T8 and dedicated fuse F8 of engine bay control unit B1 - is operated at the first speed in any case if the compressor activation request button is operated, even if control knob H81 is in position ''0''. According to its internal control logic, the control unit M10 sends the command - from pin 18 of connector A - to engage the compressor which energizes the relay T5. The activation electromagnet of air conditioner compressor in L20 is therefore controlled at a voltage of 12VIf the linear sensor for fans K120 indicates that the pressure level is too high or too low to control unit M10 - pin 75 of connector A, control unit M10 cuts out compressor activation.