2892646 - E6021 COMPRESSOR ENGAGEMENT - Functional description (Automatic Air Conditioning, Euro 3)

Functional description

The relay J20 controls the compressor engagement circuit. The relay is supplied by relay R1 : line controlled by the ignition INT/A, protected by fuse F15 : both are housed in the junction unit B1 . The supply for the relay R1 comes from the direct line of the maxifuse J/B1 of B5 , whilst the coil is supplied by the line (INT/A) protected by the fuse B26 : this line also supplies the switch unit H80 ,. via the fuse B27 . The relay J20 coil is suppiled by the line protected by fuse B39 See E5050  DIESEL ENGINES ELECTRONIC MANAGEMENT . Pressing the button in group H80 , sends a signal to the climate control system control unit M70 - pin B5 - ; this checks the conditions for engaging the compressor and sends another signal to the 4 stage pressure switch K10 at pin A13. This, in turn, if the pressure in the circuit is correct, does not interrupt the signal which reaches the engine control unit M10 (pin 60 of connector A). Control unit M10 uses its own internal software to send a signal (from pin 18 of connector A) to activate the compressor which energizes the relay J20 . The relay operates the solenoid valve, at 12 V, which switches on the air conditioning compressor L20 . The engagement of the compressor is also controlled, in the same way as described above, by the switch I65 for the 'MAX DEF' rapid demisting function.