New alternator not charging

Forgot about this thread, just had a PM from another member asking what the outcome was so here it is,

Not having any formal training the best I could to was tracing the fault to the wiring to the alternator, I believe it had a high resistance. I referred the customer to a nearby VAG specialist to get a better diagnosis. He then came back telling me that they said it was the new alternator. I told him to pay them to replace it and if that fixed the fault we would reimburse him. Never heard from him again.