Relays T06 and T07 of engine compartment junction unit B001 manage fan N001 activation at the two set speeds according to the engine coolant temperature and the air conditioning circuit pressure levels.The coils for relays T06 and T07 are directly connected to battery A001 (connector E) via pin 79 connector A of B001, while the respective power contacts are protected by fuses F06 and F07 of B001.Engine coolant sensor/sender unit K036 receives a reference earth from pin 29 of connector B of engine control unit M010 and sends a signal proportional to engine coolant temperature to pin 54 of the control unit.Linear sensor K120 notifies control unit M010 (pin 87 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 Linear sensor K120 receives a power supply and reference earth at pins 37 and 10 respectively of connector A of engine management control unit M010.When engine coolant temperature or coolant pressure is at level 1, relay coil T06 (pin 28 of connector B of B001) is excited by an earth signal from pin 7 of connector A of control unit M010; when the appropriate contact closes, power reaches fan N011 via pin 29 of connector B of B001 through modulating heater coil O010, which causes the fan to turn at speed level 1 (low).When engine coolant temperature or coolant pressure reaches the highest level, relay coil T07 (pin 27 of connector B of B001) is excited by an earth signal from pin 8 of connector A of control unit M010; when the appropriate contact closes, power reaches fan N011 via pin 26 of connector B of control unit B001, which causes the fan to turn at speed level 2 (high).Fan N011 is connected to fan earth C045.