The relay T5 for the engine compartment junction unit B001 controls the circuit for engaging the compressor.The power supply for the relay arrives via the direct battery line protected by fuse F19 of the engine compartment junction unit.The power supply for the compressor relay feed coil T5 arrives directly from the main injection relay T9. In this case too there is a direct battery supply. See E5030 PETROL ENGINES ELECTRONIC MANAGEMENTOn versions with manual air conditining, the climate control unit M070 sends the enablement signal for engaging the compressor from pin 16; whilst on versions with automatic climate control, this signal is sent from pin 7 of connector A.The engine management control unit M010 receives the engagement request at pin 2 of connector A.On the basis of its own internal control logic, the control unit M010 sends the command - from pin 48 of connector A - the effective engagement of the compressor, which energizes the relay T5 via an earth signal. in this way the air conditioning compressor engagment solenoid L020 is operated with a 12 V voltage.For versions with automatic climate control, if the activation of the compressor is effective, this signal is sent via the CAN from the engine management control unit M010 - pins 21 and 37 of connector A - to the climate control unit M070 - pins 1 and 10 of connector A - for the climate control system display and management logics.The Body Computer M001 manages the Gateway for communication between the C-CAN and B-CAN. See E1050 CAN CONNECTION LINESIf the linear sensor for the fans K120 signals to the control unit M010 - pin 56 of connector A - that the pressure value is too high or too low, then the control unit M010 excludes the engagement of the compressor.