3315735 - E6021 COMPRESSOR ENGAGEMENT - Functional description

Functional description

A specific button on the climate control controls unit H80 enables the operation of the air cooling circuit; but the switching on of the compressor is managed by the control unit M70 in accordance with a complex operating logic -for more details, see Characteristic of working principle 5040 AIR CONDITIONING CASING AND COMPONENTS .

Relay R3 , connected to relay unit B3 , controls the compressor activation circuit. The relay is supplied with power directly from the battery - junction unit A5 - by a line protected by a special fuse F5 , also located in B3 . The coil receives a supply controlled by the ignition (INT/A) from the line of fuse F5 ; the relay is energized by an earth signal coming from the engine management control unit M10 (pin 18 connector A); in this way the air conditioning compressor engagement electro-magnet L20 is operated through a voltage of 12 V. Climate control unit M70 (pin 6 of connector B) sends an enablement signal for compressor activation to four-stage pressure switch K10 ; if circuit pressures are correct, the signal leaves the pressure switch and reaches engine control unit M10 (pin 6 connector A). According to its internal control logic, the control unit M10 sends the command to engage the compressor which energizes the relay R3 .