97 Cavalier - Alternator hum with engine off
Alternator hums with the engine off, ignition off. Why? Is this normal, will it cause battery drain?
Are you sure it's from the alternator? Possibly diodes or internal
regulator, but I would get a good charging system check ASAP.
If you are energetic you could remove the alternator and take it into an Autozone type store and get a free check on it.
[FONT=Arial]Yes it is from the alternator. I also suspected the diodes or internal regulator but do not notice any hum or whine in the radio, mostly was wondering if anyone else had experienced this before. It sounds like a small A/C inverter. It would take me longer to drive the alternator to the autoparts store than to R&R the unit. I guess I will do a bit more troubleshooting.Thanks for your feedback.
see if your pulling any current from the battery with the ignition off.