Okay, this cropped up yesterday on my '71. I have had issues for a while, it's getting worse now.
Truck is a '71 C10 w/ a stock 350. Externally regulated alternator. Both alternator and voltage regulator were replaced over the summer. Wiring is good. Clean wires, no splices and I just rechecked the wiring today.
Symptoms started out as thus: At idle the ammeter was in the middle, little above half. Turn on the lights, heater fan, or wipers and the needle would drop and then all of a sudden the regulator would open up and the needle would swing way over. Once it stopped charging the needle would drop to the discharge side again and the cycle would repeat itself.
Now, it has gotten to where the swinging is gone. The needle sits the same as it did before at idle. It does come up a little when revving the engine. However, now I turn the lights on and the needle drops to the discharge side and stays there, no swinging up anymore. Last summer I did a voltage check after replacing the alternator and regulator and it was running 14 - 14.5 at both alternator and battery. I just checked it this afternoon and it's running 12 - 12.2 at alternator and battery at idle. If I turn the lights on and check the battery side I can watch it go from 12.2 down to 6.00 and back up.
So.... I'm thinking I have an issue with my regulator. Sound right or am I missing something?
Last edited by Bears63; 12/19/2009 8:45 PM.
