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Clayso, Master Automobile Technician
Category: Dodge
Satisfied Customers: 880
Experience:  ASE Master Certified Automobile Technician. 30 Years Experience.
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I have an issue with my 1996 dodge 3500 not charging. The

Customer Question

Hello, I have an issue with my 1996 dodge 3500 not charging. The gen light came on and I checked to see if alternator was charging and it did not seem to be. Voltage was under 12V when running. I changed alternator and it is still doing the same thing. I will be honest and say that when changing alternator I forgot to disconnect battery terminals and shorted out the B+ wire on the back of the alternator. This blew a 120 amp fuse which I replaced. But even so, the charging system is still giving the same problem of not charging.
Submitted: 2 years ago.
Category: Dodge
Expert:  Clayso replied 2 years ago.

Hi There, I'm Clayso a certified master automobile technician with 30 years of automotive repair and diagnostic experience.
From your description most likely you have a PCM problem. The PCM controls the generators output. The Electronic Voltage Regulator (EVR) for the charging system is in the PCM. To check the EVR the engine must be cold. Disconnect the negative battery terminal and connect a digital voltmeter. Red to battery positive and black to the generator field wire, this is usually a dark green wire on the back of the generator. Connect the negative battery terminal and start the vehicle.
The EVR voltage on the voltmeter changes to fast to be seen on a regular meter, and there is no specific voltage reading, but the meter will show an average voltage. Have someone turn on all electrical loads (lights, fans, wipers...). The average voltage should increase if the EVR is working properly. This average voltage should increase and decrease as electrical loads are turned on and off.
If the parts store still has your old generator have them bench test the unit or remove the new and have it bench tested off of the vehicle. If the units test good the problem is most likely the PCM or the wiring to the PCM.
Charging system problems most always set codes. If the check engine light has been on with the engine running, have the system checked for codes and let me know if any are found.
I hope this information is helpful to you. Should you have any questions please let me know.
Kindly rate my assistance in a positive manner so I may have credit for helping you.
Positive ratings are greatly appreciated.
Thanks so much.