Alternator Wiring Issue Question

I went to drive our 1929 town sedan and the battery was completely dead. This has happened before, the last time was about 4 weeks ago. The car runs great, then the next day or so – no battery. The ammeter is at 0 when I push in the pop out switch and release it (take my finger off, I do not see it move to discharge). The distributor is between cylinders. Do I suspect the switch or a bad spot in the alternator that is letting the current flow backwards? Thank you for taking your time to answer this question.

Answer:
Make sure the black wire from your coil is connected to the terminal box stud that has the yellow wire with black tracer. This should be the (+) side of the Ammeter. The (-) side of the ammeter (yellow wire) should connect to the other terminal box stud, along with the yellow wire from the starter motor. No other wires should be connected to the Yellow wire stud at the terminal box. All other wires should be connected to the terminal box stud with the yellow wires with black tracer. This will ensure that all electrical circuits will pass through the ammeter and all current drain will be detected on the ammeter. The ignition switch is connected between the coil and the ignition points and is used only to apply voltage to the points.

No other electrical circuits are affected or connected by the ignition switch. The ammeter should always show any current drain in the circuit. Watch the ammeter while disconnecting the battery (fully charged battery) to determine if a slight discharge is indicated. Disconnect the electric windshield wiper and the single wire from the generator cutout (or the alternator) to see if it causes any slight movement of the ammeter to indicate a slight discharge. If you have an alternator installed, and getting a current drain through the alternator, it indicates there is a bad diode in the alternator. If you have a generator with a cutout installed, the cutout relay may be bad and not opening, allowing the battery to drain through the generator. I hope this allows you to isolate the source of drainage. – Les Andrews, 1998 Technical Director