Audi Main Dealers

[The Kowalski]

CAN YOU TRUST YOUR MAIN DEALER ? My father perchased an '03 A8 about six weeks ago. Last week the wipers abruptly stopped working. As a matter of course I checked the fuses and found no fault, so logically, I assumed that the motor had failed and contacted Audi. They said that if we took the car to them they would diagnose the problem for £125.00, which would be deducted from the cost of repair, if we let them do the work. This is all very reasonable, UNTIL, Audi confirmed that their diagnosis confirmed that the motor had failed and the cost of replacing it was going to be £500. Dad and I discussed our options, and decided to look for a secondhand unit on the web. We found one for £95 and it was delivered the next day. Yesterday we started the swap ( no haynes or similar available ). After 2 hours the job was done.
HERE'S THE PROBLEM, with the new unit installed, and everything working properly, I had a look at the faulty unit, bear in mind that Audi said that the motor had failed and it was going to be £500 to replace, I turned the unit over and saw that the 13mm nut on the motor drive was loose. I now have a spare unit that is 100% working.
Did Audi do a diagnosis £125 , I'm not sure. If they did, how do they explain the fact that the motor is mint.
This isn't the first problem i;ve had with the dealer concerned, but it is the first that i've actually caught them out. Can you trust a main dealer ?
I DON'T THINK SO !!
Has anyone had similar problems ?

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