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over the past few days its been rather cold, but the truck has done fine in the winter so far, but now it wont hold a charge. how long does it take for the alternator to charge up the two batteries? the batteries were tested a couple months ago and tested fine. Could they go bad that fast? could this be the alternator? everything ive read about bad bad alternators is teh gen light comes on and the lights stop working. I apreciate the help. thanks
 

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My bet is if you used the grid heater and started the engine it would take at least ten minutes to replace the juice you just used.

What your dash volt gauge saying?

My bet is your batteries are bad, just because they are newer doesn't mean much.
I've had more new batteries fail in the first month than when they are over three years old.
 

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Discussion Starter #3
the volt meter shows 14 or 15. the batteries arnt new i just tested them a couple months ago. with a jump it fires right up. what about if the batteries were dead? an hour?
 

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I have the same problem right now, mines sitting a Freedom Dodge waiting on the PCM to come in. Very Pricy, The PCM itself is about $600. Mine wouldnt hold a charge at all, put new batteries and 2 new alternators on it and didnt help, so i took it there and they looked at it and my PCM went out, althought i think its jus the voltage regulator in the PCM, but they have to program the PCM with the truck. my final price is $1000 and i get it back monday thank god
 

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Def bad batteries....if u put them on a charger over nite and then they go dead ...also try disconnecting them over nite just incase u have a short thats draining the batts
 

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i also tried a new crankshaft sensor bec my tach and speedometer quit but it didnt help
 

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I know it's too late

I have the same problem right now, mines sitting a Freedom Dodge waiting on the PCM to come in. Very Pricy, The PCM itself is about $600. Mine wouldnt hold a charge at all, put new batteries and 2 new alternators on it and didnt help, so i took it there and they looked at it and my PCM went out, althought i think its jus the voltage regulator in the PCM, but they have to program the PCM with the truck. my final price is $1000 and i get it back monday thank god
I wish you would have posted this before you went to the dealer. This fixes it for about $25.

FAQ

Floyd
 

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Ooof, that bites. Yeah, the old style mopar voltage regulator can be easily wired in to take the place of the pcm's voltage regulator function. Of course, that doesn't get you the gauges working again.
 

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Yeah thats why i just went ahead and had them replace the whole PCM, if that doesn't fix the problem they will have it till its fixed completely. But i did kno about the wiring the replace the PCM's regulator. Oh well lets jus hopes this does the trick lol
 

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Problem with the dealer and PCMs is the new generation of mechanics don't know how to diagnose problems, they depend on the PCM to tell them what's wrong.
If the PCM doesn't tell them what's wrong they automatically assume it's bad, replace it and still have the same problem.
More often the problem is a bad connection rather than the PCM and just replacing the PCM will temporary fix the problem by wiggling the wires and connections around. You get down the road 1000 miles, it fails again and the dealer says sorry, no warranty on electrical.
I've ran into this problem more times than I care to count and know several people who have ended up with two good expensive PCMs.
 
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