air con clutch or control module fault???

[Markeyboy]

iv had no aircon since i purchased my a3 over a year ago

when i switch the aircon on (econ off) the second fan at the rad comes on, but the clutch for the compressor does not come in

i have got the plug off of the compressor and measured the voltage across it, it seems to be a constant 9 ish volts regardless of the air con being on or off, and when switched on the volts rise to 10v for moment and then back to 9v

i have not been able to get to the connections on the compressor to check the coil (assuming there is one in there???)

i dont get any vagcom faults when scanning the car relating to aircon, is there anything else i can check?

 

[Markeyboy]

Any one?

 

[Markeyboy]

Please help me, I'm too hot =(

 

[danphipps]

I have just the same problem but when i switch the econ button on ( air con off) my 9 volts go, the only thing switching the bair con on/off is this 9volts to the compressor if 9 volts isnt there it sont engage if it is there the clutch should engage. I have been looking on the internet and dont entertain the idea for a second hand compressor but the cheapest i have found is 210 + vat from a website called fastrads its a common problem with these cars and a/c pumps some audi garages deny it others tel you its very common, replace the compressor and it will solve all your troubles let us know how you get on

 

[Markeyboy]

when i get chanve im going to make up a plug to chech the resistance through the coil in the clutch, then stick 12v up ity and see if it opperates,

will probably be next week at the earliest

 

[Andy_TDi]

Yup i'm having the same problem i even ran a 12v supply seperately to the compressor it's self still no aircon nor does the clutch plate engage so it's looking like a new compressor also resistance is 10ohms where from what i've read it should be 3.6ohms

 

[AudiLeon]

Have you tried a new clutch relay?

 

[nddy]

I am experiencing a similar issue my a4 b6 compressor clutch fell off.