ALternator question 1970 Swinger 340

Brushes are one possibility, but please don't start by "throwing parts" at the car, which is about the same as throwing money in the garbage.

First, "new regulator" (part) does not mean a "good" part.

Notice you have a blue and a brown wire hooked to two separate "pull off" terminals on your alternator.

With engine off, turn on the key, and verify that you have "battery" voltage on the BLUE wire to ground.

If so, pull the GREEN wire off the alternator terminal, and stick the meter on the exposed alternator terminal. Verify that you again have "battery."

Now take a clip lead and hook the exposed terminal to ground, start the car, and see if it charges by carefully increasing RPM on the engine.

If so, you have a wiring/ regulator problem.'


If not, you have an alternator problem. It might be brushes. It might be something more serious, but it IS in the alternator according to the previous tests.

Forgot to add, if it does not charge, before you condemn alternator, make sure output stud is actually hooked to battery. While doing the charge test, if ammeter does not show charge, put your ammeter first on battery, ref engine easily, and check for increased voltage. IF NOT move meter to output stud of alternator and check for increased voltage at the stud.

THEN.. if no charge you have an internal alternastor problem.