2000 Tundra

Battery indicator light came on while driving a few minutes ago.

Duralast Gold battery. It's one year old.

Gonna check battery first and hope it's not the alternator. I don't want a new alternator for Christmas.

Don't recall having the battery light come on like this last time a battery went out on me.

1) Is alternator belt intact?

2) Stick a voltmeter on the battery when the engine is running. Should be approx 13.8 volts. If 12 v or lower, alternator is likely dead

Don't have one with me but will check the belt.

Gonna head to Autozone soon and get the battery tested.

When the light comes on, it's because the voltage has dropped. If alternator was working, light would be out, pretty much regardless of if there is even a battery connected.

Volt meters are about $10 at Walmart. ;0

I have a voltmeter.

It's at home.

I'm at work.

CanyonAg77 said:

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When the light comes on, it's because the voltage has dropped. If alternator was working, light would be out, pretty much regardless of if there is even a battery connected.

Volt meters are about $10 at Walmart. ;0

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This ^

Should be an alternator shaped light.

I have never had the light come on when the battery went bad. Only when the alternator went out.

I have had a bad battery kill an alternator, however. Basically the weak battery needed constant charging and eventually killed the alternator so when I replaced the alternator it also needed a battery.

maroon barchetta said:

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Don't have one with me but will check the belt.

Gonna head to Autozone soon and get the battery tested.

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Single belt, yes?

Power steering and A/C would be out if you lost the belt.

And now the light is off.

I'm gonna go get the battery tested anyway.

maroon barchetta said:

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And now the light is off.

I'm gonna go get the battery tested anyway.

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They can test the alternator too.

a bad diode in the alternator can give intermittent non-charging periods. Usually heat related.

If they can't find the issue, start carrying your volt meter (and a pair of jumper cables) and test it when the light comes back on.

Everything tested good.

I will check it with a voltmeter if it happens again.

Appreciate the input from everyone.

1997 7.3 F250 here. Battery light would come on intermittently. Ended up being a bad pulley on the vacuum pump that would cause the belt to hang up and conversely, the alternator was affected. Check your pulleys on all items and the condition of the belt if it keeps up intermittently

Belt was replaced last year so it should be good for another 85,000 miles or so. But I'll check.

I think your alternator is on the way out.

1agswitchin4lanes said:

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I think your alternator is on the way out.

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Yeah

The light keeps going on and then turning off for long stretches, and the gauge for the electrical system goes back to normal operating range.

I'm gonna get it looked at next week.

New alternator installed today along with new belt and battery terminal connector.