P38A Compressor

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I have 2 compressors and both of them are not working via the main built in wires, as I have changed all including 3 No valve control units. But they still don't run the compressor, the compressor only works via the manual switch.
 
Hi Guys, have not had a chance to look at the car but my question is if the valve block pressure switch is duff would that stop it all from working,as I'm looking to buy a second hand EAS unit to see if that clears the problem.
 
J L Carr said:
Hi Guys, have not had a chance to look at the car but my question is if the valve block pressure switch is duff would that stop it all from working,as I'm looking to buy a second hand EAS unit to see if that clears the problem.
Click to expand...

Possible but more likely to be the thermal switch. I had one once that appeared OK but wasn't. Not difficult to replace and only costs a fiver plus some solder. Personally I would just get a new compressor off Kurt and if it fixes it, great. If it doesn't then it can be a spare under the passenger seat for when needed.
 
If you look at RAVE it all becomes clear. Testing the compressor & pressure switch can be done without the ECU if you want. All of this is already in this thread & Wammer's guide, but repeating here just for you !!
  • Remove Relay 20 & look at the diagram on the side of the relay. This will show which pins are the contacts. Jumper these two in the fusebox & the compressor should run.
  • The diaphragm valve should also engage allowing the pump to start filling the tank. (it's powered from same relay)
  • Monitor the pressure switch either with EASunlock, Nanocom or Meter. It should close at 140 PSI, but I have several that close at 125-135 PSI.
  • Now remove jumper to stop compressor.
The thermal switch inside the compressor simply grounds the orange wire to tell the ECU the pump has overheated. ECU will not trigger RL 20 if the thermal switch is open. Also a short circuit fault in the pressure switch will probably stop the ECU running it, because the ECU thinks the tank is full !!

If all else fails you could pop down to Langley on the next non-rainy day, and I can help you check the whole system. PM me if interested.
 
Well on Saturday I put together a full EAS box, value block, valve block control unit and compressor fitted it in the car and hey presto the bloody thing works, but as soon as I switch off the back enkd starts to drop, but I think it my be them silly connection's I got to join the pipe. As it up and running (how I don't know ) it will be left alone for now, I have left the manual switch just in case. So I will have a look at the other EAS box and look at the pressure switch to see if it that. Up to now Guy's thanks for your help.
 
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