2892643 - E6021 COMPRESSOR ENGAGEMENT - Functional description (Air Conditioner)
Functional description
The relay J20 controls the compressor engagment 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 fuse B26. The relay J20 coil is always supplied by the line controlled by the ignition (INT/A) protected by fuse B27: this line also supplies the switch unit H80.Pressing the button in group H80, sends two signals:
- one to the electronic frost thermostat K86 which, if the temperature of the evaporator is not too low, sends another signal to the 3 stage pressure switch K5 . This, in turn, if the pressure in the circuit is correct, does not interrupt the signal which reaches the engine control unit M10 . Control unit M10 uses its own internal software to send an (earth) signal 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 .
- a second signal energizes the relay J34 coil which activates the first speed for the fan N85 , according to the description ( See E6020 AIR CONDITIONING ).