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Alternator mystery

Posted: Sat May 13, 2023 1:34 pm
by charlielucky
Hi, I love my fiat 2000 but sometimes...... My battery is not getting charged by the Alternator, so at first I thought I would have to replace it. On closer inspection, one of the wires with the plastic slip on connector was not connected at all. I thought this would solve the problem so I set up my multimeter to test the battery while running the car. The motor started behaving like an old stationary engine with a governor. At first I thought I must have disconnected a wire or something by accident. Just to be sure I disconnected the wire from the Alternator and low and behold the motor ran beautifully. Any idea what is going on? The wire in question runs into the wiring harness so I have no idea where it goes.

Charles

Re: Alternator mystery

Posted: Sat May 13, 2023 3:44 pm
by 18Fiatsandcounting
The wire to energize the alternator field circuit should be a black/violet wire. Is that what you connected? It goes to the battery indicator light in the tachometer.

One possibility is that your battery is really weak and so the alternator is having to work really hard to charge the battery, but I would think this would only lower the idle speed a bit, not cause it to run poorly.

-Bryan

Re: Alternator mystery

Posted: Sat May 13, 2023 5:42 pm
by charlielucky
Hi, yes the wire in question is the black/violet. It is hard to get a good look at the back of the alternator so I'm not sure if there is another terminal to attache the wire. The Alternator is a Bosch 14V 65A 21 model. 0120489823824.