Electrical Issues

[patrickt]

Originally Posted by TKlauber

One other thing. I don't remember with my car over the years but I was thinking the ammeter should read 12 -13 volts while idling to show that the battery is being charged - you sure it should be zero at idle? Tom

The ammeter doesn't measure volts, it measures the current that is travelling to, or from, the battery. Once the battery is charged, the alternator is providing all of the power that the car needs, so almost no current is headed through the ammeter to the battery -- so it shows zero. But when you turn the fans on, and the car is idling and the alternator is running slow, it is not unusual for the battery to "supplement" the power that the fans need and then you see a minus value on the ammeter. As you rev the engine up, the alternator makes more power and the the gauge swings back to zero or positive.

Your problem is almost certainly a bad connection or corroded wire -- the ground wire on the block/head is a likely culprit. It could also be the connections at the ammeter itself, but that's much less likely than the battery, starter solenoid, and block/head itself.