ok my deal is was driving to work this morning and i noticed my battery light was on so when i got to work i did a quick test i took the negetive battery cable off while my engine was running and the car stayed running i was like wow lol so i put the cable back on and shut off the engine.i came back to my car at break and started it up again in started fine no trouble so i headed to dinner and bam back on again and i noticed that when the indicator light is on the engine at still idle is idleing at 2,000 rpm is my aternator out or is it something else ty?

Bronson Bentley

Might be the voltage regulator. It is a part of your ECU so it is not replaceable. The light goes on because the voltage is dropping below the specified level. The alternator is still doing its job and so is the battery, however sooner or later the battery is going to get killed off.

The easiest way to tell is run a volt meter at idle and during operation. Do you have a UDP?

http://www.electromotive-inc.com/pdf_files/neon99.pdf

This article discusses what is needed to replace the regulator with an external one if that is in fact your problem.

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2012 2500HD LML

no UDP but today i did try changing alternators and the light is still on so i guess i'll change my PCM i hope that fixes the problem is there anything else besides the PCM that could be going bad?

Bronson Bentley

Are you seriously going to fork over the dough for another ECU?

The Voltage regulator/pigtail combo will cost you only 25.00 from autozone.

Unless you have a buddy with the exact year ECU handy to swap out, I would check cheaper alternatives prior to buying another ECU.

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2012 2500HD LML

i have 2 more ECU's in my garage lol from previous parts cars lol

Bronson Bentley

ok just changed out the ecu's tryied two of them i had in the shop and the light is still on i also noticed that when i push in the clutch like coming to a stop that the engine stays idled at lik 1500 rpm i hope that helps yall some more lol thanks and keep the ideahs comin

Bronson Bentley