Battery charge indicator - belt slip?

[seabeelt]

Alternator light is initially powered by the battery (think key on but engine off) with ground side if you will going back to the alternator. Once the alternator starts to spin, it starts to produce voltage on the "ground side " of the light and reduces the voltage differiental across th light Reduced voltage differiental makes the light go out. Normally once the alt starts to spin, this is enough to make the light to out. If it dos not go out, either the voltage regulator or the triode bridge is starting to fail. Sounds like your headlight circuit is back feeding the voltage differential Loading the alternator should make the light come on more, not turn it off. Try turning on every circuit and run the car at about 1500-2000 rpm. If light is on i'd suspect the alt
And or voltage regulator. If the light is off I'd be looking for some kind of short circuit behind th dash panel

[phaetn]

Thanks for all the replies, folks.

It's a new battery as of the beginning of the season; that said maybe a new battery was required because of whatever this problem is and it has been ongoing.

Headlights (Hella H4s) are on relays.

I have had everything running at the max load possible under nasty weather conditions driving to FFO and I didn't have any issues (lights, wipers full speed, blower on max, camera in lighter socket, etc. -- probably everything but the rad fan as we were at highway speed, but it was definitely cycling on and off many times during the trip) and it all worked ok. Never a dead battery or signals flashing slowly in well over 1,000 miles of driving in all sorts of conditions.

This alternator light glowing only arises when lights are off, and it's not always consistent. Llast year it would only happen if the RPMs were below, let's say, 650, but that was when I was driving withi lights always on. Now it's coming on at idle and well above, but that's with lights off. Maybe it would have done the same last year. It's also not solidly on, but pulses on and off. What's infuriating is that it doesn't always happen.

There are definitely times when I can hear almost a whistle from the alternator at idle but I don't think it's slipping on the belt (I have coarsely sanded the pulley for grip and if anything I have the belt too tight). The sound seems to be in synch with the pulsing of the lights. During those times I can even detect a change in voltage at the battery with a voltmeter, as well as hear the fuel pump change whine.

I wonder if I'm wasting my and everyone else's time worrying about this. I keep telling my kids that the secret to a happy life is to be content with what you have and not worry about what you don't have. Maybe I should just heed my own advice.

I'll keep my eye on it and if it actually becomes problematic in terms of car operation rather than just an annoying dash light then I'll swap out the alternator...

Thanks again for all of your ideas!

Cheers,
phaetn