p38 4.6 eas problems

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When you drive the compressor from diagnostics you cut out the temp switch and pressure switch. The fact that the compressor can be run from diagnostics proves the circuits from ECU to relay 20 and from fuse through relay 20. So the only two things that can be stopping it from running are the pressure switch circuit or the temp switch circuit. So unless both your ECUs are knackered one of these MUST be the cause. There MUST be continuity from Orange wire to Black wire to prove temp switch. If there is it can only be pressure switch circuit.
 
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Is it possible that the prat who fitted the springs has fitted a wiring bypass or even disconnected/cut something in an attempt to kill the fault messages. I know that this should be done on the ECU but did he?

Have you got a delay relay fitted?
 
hi thanks for the replies dont feel quite so alone now lol i tested the thermo switch by shaving back a small section of the orange wire just as in the link & ground it to earth it didnt run either but to be on the safe side i fitted a brand new one i also fitted a brand new pressure switch (the green one on valve block) still wont start. there was a wire fitted to ecu plug when it was on springs this is removed. when i first fitted air bags & ran software there was a few faults one of which was a height sensor this was rectified & faults cleared. currently there are no faults logged but compressor still wont start automatically. i have drained all air from system, still wont start also yes there is a delay relay fitted if i unplug this it throws up a fault message
 
If the compressor runs from diagnostics that proves circuit from ECU to relay. As i think i said earlier there can only be two things preventing it from running automatically. One is temp switch other is pressure switch. The compressor circuit is very simple. Time to get out your multimeter and check again continuity from Black wire to Orange wire if you have that, for voltage across pressure switch wires and back to ECU. Look at RAVE for ECU pins to pressure switch. It can only be one of those circuits.
 
Very slim chance, but worth a thought - does your interior light come on when you open the doors? (if not, perhaps a door switch could be faulty and bulbs removed to hide the fault)
 
hi guys just about recovered from flu so back to repairing the rangy lol i`ve just test the pressure switch for continuity there is no change of state from empty of air to full pressure
this is the green switch fitted into the valve block i believe i had just replaced this with a brand new one, could this be faulty?
 
gregyzfr1 said:
hi guys just about recovered from flu so back to repairing the rangy lol i`ve just test the pressure switch for continuity there is no change of state from empty of air to full pressure
this is the green switch fitted into the valve block i believe i had just replaced this with a brand new one, could this be faulty?
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If it's a Britpart part it could. How did you check full pressure? Cut out pressure is 9.5 to 10.5 bar, cut in is 7.8 to 8 bar.
 
hi there thanks for the reply i ran the compressor manually for 10 mins till it reached full height once unplugged the valve block did all its clicking putting car to ride height
 
gregyzfr1 said:
hi there thanks for the reply i ran the compressor manually for 10 mins till it reached full height once unplugged the valve block did all its clicking putting car to ride height
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That does not mean it was at full pressure, 50/60psi is all that is needed for the airsprings against a storage tank cut off pressure of 138 to 152 psi. Sorry to switch to psi, I don't have the airspring pressure in bar and I'm too lazy to do the calc:)
 
gregyzfr1 said:
lol ok no worries i dont have pressure gauges etc think i might put it back to springs need to many tools & money to fix this thanks all for your help
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No tools needed to fix it other than what would normally be in your toolbox plus the EAS software and cable. Cost you a lot more to ruin with coils.
 
long day spent working on rangey & achieved nothing electrics are a dark art to me but i definately have no power to pressure switch or at pin 13 on ecu the air is low now & switch has changed state where do i find the power supply? as i have no idea rave is no help either
 
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