My friend has a 2001 VW Golf 2.0L that stopped charging. Battery voltage was 11.5 volts unloaded, and with the engine running stayed at the same voltage. I figure he could have a bad ground, bad fuse, bad relay, or bad alternator.
I charged him up enough to get the car to a European mechanic, who wants to charge $340 just for the alternator. The mechanic also said it needed to be replaced without doing any diagnostic at all except for what I had already done.
I found a black wire going to the alternator and measured resistance to ground, and found it open. Should the wires circled in the picture below show continuity to ground?
My friend doesn't have much money, and I don't like the "replace parts until it starts working" philosophy of repair work. If you know what I can check, and where to look, that would be great.