charging system

[68 440+6 R/T]

I am having a weird problem with the charging system in a 70 B body. What will happen is that the car will be charging fine and then all of a sudden the amp gauge will start to jump around to negative then back to positive some time to zero. Also some times the gauge will read negative but when you give it RPMS "maybe 1000-1500 or higher" it will start to read positive. Could this be a problem with the bulk head connector wires being loose or corroded? or the voltage regulator being bad?

 

[Kern Dog]

The field wire terminals on the alternator could be loose, the connectors may have loose spades inside, the alternator itself could have failing brushes, the wires or terminals to the voltage regulator could be pinched or damaged.

 

[PlymCrazy]

Had identical problem. Ruled out all other charging system components. Wound up being bulk head connector. Discovered it by watching the ammeter while someone wiggled the connector under the hood. Threw a zip tie around the connection to pinch it enough to get me home from a cruise one night last year.