The relay T5 for the engine compartment junction unit B1 controls the compressor engagement circuit.The supply for the relay via the line for specific fuse F19 of the engine compartment junction unit B1.The power supply for the coil for relay T5 arrives from the main injection relay T9 and from the line protected by fuse F18, both located in the engine compartment junction unit B1.Automatic climate control:The climate control system control unit M70 - from pin 4 of connector C - sends the enablement signal for the engagement of the compressor to the engine management control unit M10, pin 54 of connector A.Manual climate control:When the unit button H80 is pressed, two signals are sent:- one signal to the engine management control unit M10, pin 54 of connector A.- a second signal excites the coil of relay J34, which controls activation of the first speed of air fan N85, as described See E6020 AIR CONDITIONING Fan N85 - supplied by the ignition-operated line (INT/A) of relay T8 and specific fuse F8 of engine compartment control unit B1 is operated at first speed if the compressor activation request button is pressed, even if control knob H81 is in position "0".On the basis of its internal control logic, the control unit M10 sends the command - from pin 29 of connector A - to engage the compressor which energizes the relay T5 so that the air conditioning compressor engagement solenoid L20 is operated at a voltage of 12 V.If the linear sensor for the fans K120 signal to the control unit M10 - pin 13 of connector A - that the pressure value is too high or too low, then the control unit M10 excludes the engagement of the compressor.The linear sensor K120 receives a power supply and reference earth from the engine management control unit M10, pin 12 and 22 of connector A.