I bought my car with the suspicion that the a/c pump was kaput (or something related which makes it not work) and went to the local a/c specialist for diagnosis. He says it's not switching on and is either the solenoid switch or, more likely, the shaft has snapped and the pump is shagged, replacement cost in the region of £450 for a brand new Sanden pump, full flush, regas and 2 years guarantee - not bad as I know the dealer will charge more.

He read the fault codes that were stored and discovered that at the same time as a fault to the pump was logged, the power to several other items, including the radio aerial and the mirror indicator, had been cut momentarily. Incidentally the mirror indicator unit didn't work and required replacement and, having checked the hidden menu on the radio which shows 'Ant off', I have to assume this doesn't work either and requires replacement.

The a/c guy seems to think that there was some kind of momentary power spike before loss that stalled the pump while the clutch was engaged and snapped the shaft in the pump as it would not turn easily by hand, but did say that it was full of gas that would have been acting on the pistons. Does anybody have a clue what would have caused that and potentially killed the pump? Due to the number of electrical components that failed, I wonder if it's possible that it's killed a wire or a connector and the pump itself is fine.

Could the reverse be true? That the A/C pump stalled the alternator and the ecu cut power to all non essential items?

I suppose that's entirely true yes, and the items that the ECU dropped power to were logged as faults in the DTC.

Good point.

This is the most likely cause, the A/C pump is a known weak point on many different VAG cars.

i have a brand new one i got for someone thats going cheap if it will help anyone out just pm me

Could you PM me with your "going cheap" price please.

Cheers.

i have a brand new one i got for someone thats going cheap if it will help anyone out just pm me