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Discussion Starter · #1 ·
Hi Folks..

I'm new to the forum...... Please help me..

I am reading abnormal voltages from my alternator with a digital volt meter. It will act ok ie 13-14 volts then jump up to 16-17.5 volts. If i bring up the rpm the voltage will rise up high.....but not all the time. The voltage goes up and down while driving.

I am running a MP comp so I swapped back to the stock comp to see if it was the voltage reg in the comp. No luck...... same crap.
I put in a new battery yesterday. No help.
Any Ideas? Maybe an internal problem to the Alternator? What could I test next?

Many thanks.

Brandon

1997 Ram 5.2l auto
:mad:
 

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EPA's Worst Nightmare
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Welcome to Dodge Talk.
Sounds like the regulator in your alternator is shot. Replace your alternator. Allmost all regulators are inside of the alternator. The other thing it could be is your batt. but you replaced that, so that makes me believe that it's your alternator.
 

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Discussion Starter · #3 ·
I was reading in a manual that the voltage regulation is done in the PCM. Is there additional regulation done in the alternator?
 

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EPA's Worst Nightmare
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Really? I thought Dodge stopped doing that over 10 years ago. I haven't worked on too many dodges, mostly ferds since they break the most so I could be wrong. I'll look for my book and see if I can find it. Most alternators have regulators in-side the alternator.
Have you checked all of your connections to your batt. and alt.?
 

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EPA's Worst Nightmare
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Yeah you are right voltage regulation is done in the computer. I thought Dodge would have been smart enough to put a regulator in the alternator by now. If the regulator goes bad it takes the computer out with it. Check all of your connections since you have all ready tried swapping computers. Does it have any codes?
 

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Discussion Starter · #6 ·
MIL 46= High battery voltage
MIL 42= open or shorted fuel pump OR open or shorted auto shutdown relay OR open condition dected in auto shutdown relay output circuit OR open between BCM and fuel gauge sending unit OR no movement of fuel sender detected.

I wounder how the two could be related if any?
 

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The Legendary Cross Ram
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Bad ground? I'd check the computer ground for excessive resistance first, just in case.

Right now a wiring schematic and voltage value chart would come in handy.
 

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98QuadCabV10 said:
Yeah you are right voltage regulation is done in the computer. I thought Dodge would have been smart enough to put a regulator in the alternator by now. If the regulator goes bad it takes the computer out with it. Check all of your connections since you have all ready tried swapping computers. Does it have any codes?
This is the reason Dodge put the regulation in the PCM, the computer then has the opportunity to monitor the behavoir of the alternator at changing speed and load conditions and check that the regulator is working properly, and even toggle the regulatro on and off to check the battery response.
The 42 code might just be a high current condition in one of the monitored circuits caused by the high voltage, which could go away once the other issue is fixed, but if it's a shorted regulator output then a new PCM would be the only option. Since it's doing it with two PCMs, it's possible that there's a short to ground inside the alternator on the low side that the PCM controls (resulting in maximum charging rate) or in the wiring (dark blue??). The high side of the field to the alternator is fed from the ASD relay, but a malfunction in that wouldn't cause overcharging.
 
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