Alternator light
Thread Starter
Intermediate
Joined: Sep 2020
Posts: 33
Likes: 3
Alternator light
The alternator light on my 81 is 'slightly' on. It is just a dim glow. It does go out sometimes while driving but it glows when at idle. I am not sure if this is a short in the light or if there is a problem with the alternator or what to think. Has anyone had this problem?
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Your car should also have a voltage gauge in the center cluster. What does your voltage gauge read when your car is idling? This will tell the real story. Does it read 14 or more volts? Is it way down at 12 volts? Turn on the lights, engine still idling, what does your voltage gauge do?
Le Mans Master
Joined: Jan 2001
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Don't trust that in car gauge.
Get a digital multimeter and take a voltage reading at the battery terminals and write those readings down - as follows:
1. Car off
2. Car running at idle - no extra loads energized.
3. Car running at idle with every load possible energized (high beams, a/c, high speed fan, directional flashers, stereo, etc).
Report back these readings.
Get a digital multimeter and take a voltage reading at the battery terminals and write those readings down - as follows:
1. Car off
2. Car running at idle - no extra loads energized.
3. Car running at idle with every load possible energized (high beams, a/c, high speed fan, directional flashers, stereo, etc).
Report back these readings.
The alternator light on my 81 is 'slightly' on. It is just a dim glow. It does go out sometimes while driving but it glows when at idle. I am not sure if this is a short in the light or if there is a problem with the alternator or what to think. Has anyone had this problem?
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Usually that's a diode trio or bridge inside. Easy to diagnose and fix with an ohmmeter once you open the alternator.
But first...check ALL the fuses.
JIM
But first...check ALL the fuses.
JIM
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