Chrysler Repair: low voltage on the dash gauge, dash lights seem dim, alternator output, voltage gauge

Question
Hi,

I noticed this evening that the voltage gauge, which usually hovers ~ 12-13 volts, is now down at no more than 10 volts, with the lights on or off.  The dash lights seem a little dimmer.  I'm thinking I have a faulty alternator, since the battery is 2 months old, and cranking the engine easily at the moment.  Could this be a regulator problem?  Is voltage regulation controlled by the alternator?

Thanks,

Andy

Answer
Hi Andy,
The alternator output is what is regulated, and it appears that yours is lower than it should be. The regulation is performed by the engine controller by regulating the fraction of time that it energizes the field coils of the alternator. You didn't say the year, make, model so I can't tell you how to question the controller to see if it has diagnosed the cause of the low output voltage. Let me know and maybe we can move ahead. I think your battery will soon run out of charge if this is not corrected.
Roland