My brother and I were driving home from a concert last night, and his car dies (out of batteries)

I had my voltmeter with me, we jumped the car. His alternator was not charging. I check the voltage at the brown exciter terminal, and it shows 3 volts. Strange. The fan has 12 volts and works.

I took a piece of wire and gave the terminal 12 volts, at which point the alternator charged again and we got the car home.


If I disconnect the brown wire, I get 12 volts off of it. If it is connected, I still get three. This tells me that somewhere there is a really large resistance...


Where should I start my hunt? Any suggestions?