Components - COMPRESSOR ENGAGEMENT - Fiat DOBLO 1.9 JTD 8V da 12/03
| Component code | Description | Reference to the assembly |
| B001 | JUNCTION UNIT | |
| C10 | LEFT FRONT EARTH | |
| D004 | FRONT/ENGINE COUPLING | |
| K10 | FOUR STAGE PRESSURE SWITCH | |
| L20 | AIR CONDITIONING COMPRESSOR ENGAGEMENT SOLENOID | |
| M010 | ENGINE MANAGEMENT ECU |
| Component code | Description | Reference to the assembly |
| B001 | JUNCTION UNIT | |
| C10 | LEFT FRONT EARTH | |
| D004 | FRONT/ENGINE COUPLING | |
| K10 | FOUR STAGE PRESSURE SWITCH | |
| L20 | AIR CONDITIONING COMPRESSOR ENGAGEMENT SOLENOID | |
| M010 | ENGINE MANAGEMENT ECU |
The compressor activation button is built into the knob that selects the fan speed.The above button enables operation of the air cooling circuit, but actual compressor activation is also dependent upon activation of:- the four-stage pressure switch located on the coolant circuit that locks air conditioner activation if coolant pressure is too low or high;- the engine control unit that excludes compressor operation in accordance with engine management mode; e.g. in the case of high engine temperatures or high engine load (sudden acceleration);Enablement is also required from the vehicle interior fan adjustment knob (at least in position 1) and the demister thermostat.The compressor supply circuit is controlled by a special relay located in the engine bay junction unit. The relay supply line is protected by a special fuse.
The compressor activation circuit is controlled by relay R5, contained in engine bay junction unit B001. This is supplied directly by a line from the battery that enters at pin 1 of control unit connector A and is protected by fuse F19.The coil of relay R5 is supplied by a signal from relay R9 that in turn receives a direct power supply from the battery from pin 1 connector A.Relays R9 and R5 are excited by an earth signal from engine compartment control unit M10 from pins 72 and 79 of connector A respectively.In this way, control unit M10 controls the activation of air conditioner compressor L20 through relay R5.Engine control unit M10 connector a receives signals from the 4 level pressure switch K10 to turn on the radiator fan:- operation at first speed from pin 58;- operation at second speed from pin 81;- air conditioner activation from pin 54.
