blinking alternator light

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May 30, 2005 | 02:01 AM

walkerrim

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blinking alternator light

I have a 78 f-150 400ci that the alternator light blinks but when I turn on the lights the blinking stops. Any ideas as to why? Thanks

May 30, 2005 | 10:16 PM

Franklin2

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From: Virginia

Does it blink only when you rev the engine, or only when it idles? Is it a regular blink or sort of random?

May 30, 2005 | 11:25 PM

walkerrim

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it blinks brighter at higher rpm's sometimes it will go all day and not blink but when it starts to blink it usually does it for quite sometime

May 31, 2005 | 10:32 PM

Franklin2

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From: Virginia

I would unplug and clean all the connections out at the alternator and the regulator. Just messing around out there may fix it. Make sure you disconnect the battery before you start.

Jun 1, 2005 | 12:19 AM

Holmesuser01

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From: Asheville, NC

Any chance that this is the original alternator? Could need new brushes! I got 300K out of the original alternator on my 84 f-150

Jun 1, 2005 | 12:23 AM

walkerrim

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not sure if its the orig or not. Why would the blinking stop if I turn the lights on. Seems to me that is just the opposite of what should happen.

Jun 1, 2005 | 09:55 PM

Dealford

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From: Belleville, Ontario

Are there any signs that the battery has been getting over charged? Is there a smell of rotten eggs near the battery?
Maybe, just maybe, the voltage regulator is on it's way out.
The next time the light is blinking, check the voltage at the battery to see if it's high. Check it at idle & reved up & then with the headlights on to see what you're getting.
AL.