Alternator light question.

[Stephen B]

After sitting in the rain the other day my alternator light came on after starting the car to drive home. Gets dimmer with higher revs, but does not go completely out. Headlights / extra loads do not affect brightness - seems to be strictly RPM dependent. Voltage measures 14+ at the battery. Headlight intensity 'pulses' slightly at idle. Internal regulator was replaced about 3k miles back. Bad connection somewhere, or is the new regulator suspect?

Did a forum search and found nothing similar. Any help would be greatly appreciated.

[304065]

What kind of internal regulator was used? The Porsche one, or an aftermarket Huco or something?

The alternator lamp will come on anytime there's a potential difference across the bulb terminals. This can occur in the classical situation, e.g., the alternator output voltage is less than the battery voltage, or in the reverse situation, battery voltage is higher than the alternator voltage because the VR has failed and the path of least resistance is through the lamp, not the starter cable.

So when you say 14+, do you mean 14.5V?

[Stephen B]

John,

The regulator is aftermarket. The local alternator shop rebuilt the unit. I was seeing 14.1 -14.2 volts.

Thanks,

Steve