AC help

[Cornwall88]

Hi guys,

Car suffered from the good old leaking rear washer in passenger footwell so been sorting it all out!

AC isn't currently working, says low pressure as cause but garage say it's full of gas, is there a way I can manually engage the ac compressor to test its working before going down the route of having the compressor replaced?

Would be handy to know if I can trigger manually from a relay but unable to find any listing for the relays on the mk3!

Thanks

 

[ARH]

Did the garage you took it to not test the pressure switch? If not you would be advised to take it somewhere else. The pressure switch is one of the most common failures on AC systems.

 

[RADIOTWO]

Hi guys,

Car suffered from the good old leaking rear washer in passenger footwell so been sorting it all out!

AC isn't currently working, says low pressure as cause but garage say it's full of gas, is there a way I can manually engage the ac compressor to test its working before going down the route of having the compressor replaced?

Would be handy to know if I can trigger manually from a relay but unable to find any listing for the relays on the mk3!

Thanks

First. what has the leaking rear washer got to do with the A/C ? but they say it is full of gas but how do they know ? the only way of knowing how much is in there is extracting the old gas and putting the correct amount in.
But if you just want to check the compressor just apply 12 volt to the contacts on the compressor, and you should hear the clutch pulling in, if you don't then that might be your problem (but just make sure you get the polarity right)
So as the other guy says take it somewhere else,

 

[tracktoy]

If you have access to somebody with OBD11/VCDS they could probably do a basic settings run on the compressor or there are multiple live data elements that will show you what the compressor is doing.

 

[Cornwall88]

The washer had leaked on the connectors in the footwell and blown the fuse for air quality sensor and the pressure sensor is also on that circuit. Once wiring sorted and fuse replaced now have all reading correct but no activation still. In all fairness it was kwikfit as they don't charge for a regas is they cannot make it at least 10% cooler. It's got 510g in it as I have the print out from the machine. Suspect Compressor probably failed hence wanting to see if an easy check I can do before replacing.

 

[Cornwall88]

First. what has the leaking rear washer got to do with the A/C ? but they say it is full of gas but how do they know ? the only way of knowing how much is in there is extracting the old gas and putting the correct amount in.
But if you just want to check the compressor just apply 12 volt to the contacts on the compressor, and you should hear the clutch pulling in, if you don't then that might be your problem (but just make sure you get the polarity right)
So as the other guy says take it somewhere else,

Are you able to tell me which pin I should apply 12v to from the fuse box to test the ac clutch? Without stripping down it's awkward to get to the pins directly on the compressor

 

[RADIOTWO]

Are you able to tell me which pin I should apply 12v to from the fuse box to test the ac clutch? Without stripping down it's awkward to get to the pins directly on the compressor

Well I would start at the compressor first, and then work back, I know its difficult but then at lease you would know the compressor is ok(or not)

 

[SuperV8]

Are you able to tell me which pin I should apply 12v to from the fuse box to test the ac clutch? Without stripping down it's awkward to get to the pins directly on the compressor

Not all AC compressors have an electromagnetic clutch.
Mine (TDI) has a variable displacement compressor - which doesn't use any clutch to engage or disengage. It uses a swash plate to vary the compressor load.

 

[Cornwall88]

Thanks, problem solved, new compressor fitted as clutch failed.