312001713 - 5040BC CHECK ON CLIMATE CONTROL COMPRESSOR ACTIVATION/DEACTIVATION FROM LINEAR SENSOR

Disconnect the electrical connection for the linear sensor.    See K120 LINEAR SENSOR FOR FANS Check that Pin 1 is earthed and Pin 2 is at +5 V.Connect a linear potentiometer (full scale deflection 1 kOhm, previously positioned at around 500 Ohm between the centre pin and one of the side pins) to the pins of the linear sensor electrical connector.Turn the ignition key to the MAR position.Using a multimeter, check that the voltage between Pin 1 and Pin 3 is around 2.5 V.Switch on the engine, then switch on the air conditioning using the special switch located on the climate control system control unit.The climate control system should come on normally in these circumstances.Alter the potentiometer resistance until the voltage reading on the multimeter between Pin 1 and Pin 3 is around 0 V.The air conditioning system should switch off in these conditions because the engine management node receives low circuit pressure information.Alter the potentiometer resistance until the voltage reading on the multimeter between Pin 1 and Pin 3 is around 4.6 V.The air conditioning system should switch off in these conditions because the engine management node receives high circuit pressure information.