We are restoring our car. We are having electrical problems. we did a continuity test, from ballast resistor, both connections read continuity to ground ? Also, alternator is not charging battery. Any help would be great thanks.


Chris

How are you measuring continuity? If you are using a light or a buzzer checker, you will see continuity through all of the electrical devices including the alternator diodes to ground. A more meaningful measurement would be with an ohmeter measured to ground. Reverse the leads to read both polarities.
To measure alternator output, take the big ring lug off the alternator and insert a high current ammeter in series with the positive lead to the alternator lug. It should read around 10 amps with a fairly charged battery and normal accesories operating. If your battery is dead, it could be up to the output of the alternator (45-90 amps). No current output is a problem.
If there is no output, with the engine off, remove both of the field connectors The plastic insulated female spade connectors). With an ohm meter, measure between them and there should be around 50 to 1000 ohms. There should be no resistance to ground on either terminal.
If that is good, look at the voltages on the wires leading to them. The easiest way while avoiding injury is to pierce them with sharp probe tips a safe distance from the alternator. With the engine running, one voltage should be close to battery voltage. The other should be close to zero volts. If these are not present, it is the voltage regulator at fault. If they are and there is no output, your alternator is bad, most likely the diode pack. If there was no continuity on the field coil, the brushes or field coil is bad. I have only rarely seen the field coil go bad.
Hope that helps.
Craig