The relay T17 for the engine compartment junction unit B1 controls the compressor engagement circuitThe supply for the relay via the line for specific fuse F34 of the engine compartment junction unit B1.The power supply to the coil of relay T17 reaches relay T6 of B1: this ignition-operated supply (INT) is controlled from pin 1 of connector A of M1.On versions with a manual climate control system, the compressor activation button is located in control unit H80, which sends a signal to pin 49 of connector A of Body Computer M1, which sends an enablement signal to engine control unit M10 via the CAN.Control unit H80 si supplied from a line protected by fuse F24 of engine compartment control unit B1 and from relay T6 of B1: this ignition-operated supply (INT) is controlled from pin 1 of connector A of M1.With the compressor enabled and engine started, fan N85 is operated at the first speed. See E6020 AIR CONDITIONING On versions with an automatic climate control system, climate control unit M70 sends an enablement signal via the CAN to activate the compressor - via Body Computer M1 - to engine control unit M10.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 T17 so that the air conditioning compressor engagement solenoid L21 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.