3315733 - 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 see DESCRIPTION AND OPERATION: 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 thus energized by an earth signal coming from the engine management control unit M10 : in this way the air conditioning compressor L20 engagement electro-magnet is operated through a voltage of 12 V. Climate control unit M70 - pin 6 of connector B - sends a compressor enablement signal to four-stage pressure switch K10 . If circuit pressures are correct, the signal leaves the pressure switch to engine control unit M10 : Control unit M10 uses its own internal software to send a control to activate the compressor, which in turn excites relay J20 .