QuestionI have a 67 chev caprice that has been stored for a few years. Replaced the battery, fired it up and upon shutting if off I noticed that the generator light came on. It is not on while running just when shutting it off. Any ideas??
AnswerHello Dave,
This is a little bit of a puzzler as we're dealing with an "Idiot light" for information! And I'm not sure if you mean the light glows AS the engine turns off or AFTER the engine turns off?
The function of the light is to replace an ammeter gauge as used by older cars. It basically measures a discharge condition when the alternator is not turning fast enough to charge the car/battery. (I'm assuming what you mean in your note that the light remains glowing after the engine is shut off, key removed. If the light just glows with the engine off, ignition key in "engine on" position, this is normal for the reasons stated above)
But, I think that if a discharge condition occurs after the engine is off, the light could glow also.
To find the source of the problem, you need to have a real ammeter test gauge and have the charging system checked. I suspect a shorted diode or similar in the alternator could be one cause as it would cause a discharge condition even with the engine off.
If you don't have an ammeter, most auto parts places and/or Sears will check your charging system for free. Using real data as a base point, you should be able to determine if something is amiss in the charging system or if the fault is in the idiot light itself. Remember, many of these factory gauges weren't that accurate to begin with so I wouldn't be surprised if the gauge or voltage sensor were defective.
As you can see, you'll have to play a little detective work to track this down but having good data is your starting point'
Good luck on this fine car!
Bob
