Voltage Idiot Light
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From: Upstate NY
Voltage Idiot Light
Maybe someone can help? It seems that when I first start my truck the voltage light seems to come on stady sometimes and then other times it flickers. I checked the voltage at the aux pcm it reads 14.4 at idle at start up. Just for kicks the next morning I checked it at the batteries and it also read 14.4. I just replaced the alternator last summer so it probably has about 20,000 miles on it at most. But I dont think that that is the problem with the voltage readings. Has anyone else had this occur. I dont want to be out on a trip and have something fail. Thanks
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From: NorCal
Your batteries should not read 14.4 when the engine is off. It should be around 12.8V or so. Did you check the votlage with the engine off? When the engine is on the alterator bumps your voltage to 14.4V to charge them up.
Last edited by ebbnflow; Apr 13, 2007 at 04:25 PM. Reason: added more
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From: Upstate NY
oh, sorry that is with the truck running, and it is at 12.6-12.9v, with the truck not running. Is their a sensor somewhere that can be replaced or is it in the alternator? Thanks
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From: Upstate NY
ok, thanks i will check that. Last night it happened again and thier seems to be a draw on the system as the head lights dimmed a little but the volatge didnt drop below 14 volts. After the lights were bright again the voltage light went out, any ideas on what could be causing a draw with the engine at op. temps?
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Originally Posted by Brian0445
ok, thanks i will check that. Last night it happened again and thier seems to be a draw on the system as the head lights dimmed a little but the volatge didnt drop below 14 volts. After the lights were bright again the voltage light went out, any ideas on what could be causing a draw with the engine at op. temps?
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From: Upstate NY
I just replaced the batteries last winter about 3 months ago with mastercraft batteries, 3rd set and I am happy with them. I think cookie88 hit the nail right on the head about the voltage regulator.... This will be the 3rd rebuilt alternator in 2 years. When I replaced the alternator the first time i wanted a new one from ford, they had only one, brought it home and noticed that the box had been droped and the shaft and pully wouldnt turn so I got a reman from the local parts store (carquest). I truly belive that they have a bunch of retards rebuilding these things, or they just replace the broken components. I got the 2nd replacement at no charge but it is stupid to keep changing junk with junk, even if its free. Guess Ill call the local stealership to get a price quote.
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From: Mountaintop, PA
Wouldn't by disconnecting the red batt cable going to each battery, THEN testing each battery individually, give you a better reading on each one. I was understanding that with the red batt cable connected across the two will allow a trickle to and from each one. This way you can find a dead batt out of two. Just wanted to make sure you are doing it right.
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From: NorCal
Originally Posted by Brian0445
Maybe someone can help? It seems that when I first start my truck the voltage light seems to come on stady sometimes and then other times it flickers. ... Has anyone else had this occur. I dont want to be out on a trip and have something fail. Thanks
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From: Alberta
Check the small connector on the top of the alternator. If it is loose or not making a good connection the idiot light will come on and go off or stay on. Also the voltage gauge will jump and sometimes stay at a higher than normal reading.
Last edited by copper; Apr 16, 2007 at 09:55 PM. Reason: punctuation
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