Battery Light

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Sep 12, 2006 | 03:51 PM

The Way Out

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Battery Light

My battery light started flickering off and on. May stay on for awhile then go off.

I replaced the alternator last April with a Motorcraft from Checker. I had to drive about 30 miles to the nearest town before I could get to a parts house.

Anyway, I took it over to Checker and they checked it on the truck. He said it was working fine under load, but not under idle. I took it off and he checked it on the machine and it worked fine. He warrantied it anyway, but on the way home, same problem.

Shows to be putting out ~13.5 volts on the back of the alternator as well as at the batteries. I have an appointment to take it to a shop on Thursday, but would like a few ideas to try before that.

Thanks in advance.

Sep 12, 2006 | 06:12 PM

Uzumati

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From: Central, Al

Have you disconected the batts and load tested them individually??

Sep 12, 2006 | 06:41 PM

The Way Out

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I have not, but I will.

Sep 12, 2006 | 08:56 PM

The Way Out

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Had the battery's load tested individually and they both checked out fine. Battery light stayed on the entire way home. Checked it again and I'm getting 14.1v at the battery and 14.11v on the back of the alternator.

I mispoke earlier. The new alternator is an Autolite, not Motorcraft. I threw a breaker bar on the belt tensioner and had my daughter start it while I added extra tension.

Any thoughts will be appreciated.

Sep 12, 2006 | 09:15 PM

Uzumati

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From: Central, Al

Is the dash battery gauge doing anything when the light comes on? those voltages look pretty good. What do they do with increased RPM 1500 -2000 rangeandalso how much do they drop during cranking

Sep 12, 2006 | 09:23 PM

PowerstrokeJunkie

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Quote:

Originally Posted by The Way Out

I mispoke earlier. The new alternator is an Autolite, not Motorcraft. I threw a breaker bar on the belt tensioner and had my daughter start it while I added extra tension.

Any thoughts will be appreciated.

Welcome to FTE. a helpful note if you want to load the alternator down, is to not put more belt tension on the pulley, it will only add more tension to the bearings inside, causing premature wear. the spring in the tensioner puts all the tension the pulley needs. what you need to do is drive the truck or powerbrake (not really recommended) to put a load on the engine if you so desire. plus, putting a breaker bar on the tensioner near that circulating belt and giant fan is just dangerous.

Sep 12, 2006 | 09:54 PM

The Way Out

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Quote:

Originally Posted by amiller93

Is the dash battery gauge doing anything when the light comes on? those voltages look pretty good. What do they do with increased RPM 1500 -2000 rangeandalso how much do they drop during cranking

The guage on the dash doesn't do anything. Sits at what looks like 14v, and never moves until you shut down the engine. Increased engine speed will cause about .05 fluctuation. It will bounce up then then down a little and hold steady. During cranking, it drops about 1v, then comes back up as soon as the engine starts.