Battery light

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May 6, 2015 | 10:13 AM

andym

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Joined: Mar 2002

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From: Bonita Springs FL

Battery light

I just noticed this happening the other day. Sometimes the battery light will come on for a second then go off. It seems to happen when I accelerate. I've watched the battery gauge and it never moves when the light comes on. I have a digital voltmeter that plugs into the cigarette lighter and it reads 14.2 volts constantly, even when the light is on.

So what could cause the battery light to go on besides a drop in voltage?

May 6, 2015 | 11:35 AM

afullexcursion

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Joined: Mar 2015

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It is my understanding 13.8 volts is the max a battery should be at. Anything over that is overcharging the battery. Perhaps the alternator or voltage regulator within the alternator is about to go out?

May 6, 2015 | 12:41 PM

andym

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From: Bonita Springs FL

I guess I should have been more specific. The voltage is 14.2 only when the truck is running.

May 6, 2015 | 01:20 PM

bcrewcaptain

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Joined: Dec 2006

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From: Central Va

As my alt was dying, it would kick the light on at idle, and if loaded down, at mid throttle. very well could be the truck giving you the false reading, check the voltage at the alternator terminals, clean all connecions, then load the system with accesories...and see if you're still getting the reading. it the voltage is still stable and within range you can then start narrowing it down.

May 6, 2015 | 01:55 PM

FordxFour

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Joined: Jun 2004

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From: Apex, N.C.

The first thing that I would check is the belt and tensioner. May be slipping when you accelerate.

May 6, 2015 | 02:32 PM

2wdDezlX

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Joined: Oct 2014

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From: Prescott, AZ

Quote:

Originally Posted by andym

My 03 6.0 is doing the same thing. I'll have to see if I can monitor the voltage the same time it does it. It did sit for awhile when I was doing the hpop at the end of year and had to be jumped. Then I got rear ended and it was at the body shop for 6-8 weeks and I think they let the batteries die and just jump it to move it. With running the batteries down and having the alternator charge could cause it to go out when it could have been the batteries only. So, I may have to change alt and the batteries soon. But, I'll be watching to see what you find out also.

May 18, 2015 | 12:33 PM

andym

Thread Starter

Post Fiend

Joined: Mar 2002

Posts: 19,402

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From: Bonita Springs FL

So it turns out that 99.9% of the time when the battery link flickers like this, it needs a new alternator. I got one from the Ford dealer and no more flickering light. Easiest alternator I've ever changed before, too.

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May 19, 2015 | 08:12 AM

melonas

5th Wheeling

Joined: Jan 2012

Posts: 29

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From: Santa Clarita, CA

Check the plug first

Before you buy an alternator have someone sit and watch for the light while you jiggle the connector at the top of the alternator. I found that out on my 2005 V10 after replacing the alternator.

May 19, 2015 | 07:37 PM

#10

jeremiah77

Junior User

Joined: Oct 2014

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I had the same problem with mine. The light would randomly flicker on and off. The batteries were old, so I replaced them first. Didn't help much. Then I replaced the alternator, problem solved.