Relays T06 and T07 of the engine compartment junction unit B001 manage the engagement of the fan N011 at the two speeds depending on the temperature of the engine coolant and the pressure in the air conditioning circuit.The coil for relays T06 and T07 are connected directly to the battery A001 (connector E) via pin 79 connector A of B001, whilst the power contact is protected by fuses F06 and F097 of B001.Engine coolant sensor/sender unit K036 receives a reference earth from pin 29 of connector B of control unit M010 and sends a signal proportional to engine coolant temperature to pin 43 of the control unit.The linear sensor K120 notifies the control unit M010 (pin 57 of connector A) of the pressure of the refrigerant thereby allowing the control unit to exclude the engagement of the compressor if the above pressure values are not within the preset range. See E6021 COMPRESSOR ENGAGEMENT The linear sensor K120 receives a power supply and reference earth at pins 28 and 7 respectively of connector A of the engine management control unit M010.At the 1st engine coolant temperature level or refrigerant fluid pressure, the coil for relay T06 (pin 28 of connector B of B001) is energized by an earth signal coming from pin 13 of connector A of control unit M010; when the dedicated contact closes, the power supply reaches the fan N011, via pin 29 of connector B of B001, through the adjustment resistance O010 which determines the rotation at the 1st speed (slow).For a higher engine coolant temperature level or refrigerant fluid pressure, the coil for relay T07 (pin 27 of connector B of B001) is energized by an earth signal coming from pin 12 of connector A of control unit M010; when the dedicated contact closes, the power supply reaches the fan N011, via pin 26 of connector B of B001, which rotates at the 2nd speed (fast).The fan N011 is also connected to the fan earth C045.