Engine/Transmission (1994 - 1998) Charging System Problem

[Monroefiredog1]

Today I was ridding down the interstate and I noticed my gen light was on, I looked at the gauge and it was only showing about 10-12 amps. I thought that the alternator was bad so I went to Auto Zone and they checked it on the truck and said it must be bad, only putting out about 10-12 amps. I then removed the alternator and they tested it on the bench and it was putting out 14 amps, alternator is good. The gen light is still on at times when above a idle. Has anyone ever had this problem and if so, what was it. I know that the output of amps is controlled by the PCM, do you think it is bad? I an out of town and need it fixed so I can return home on Monday. Any help on this matter will be greatly appericated.





96 Ram 2500 diesel, stock eng, new rebuilt trans.

 

[Howard Durand]

I think you are talking about voltage instead of amps.

14 volt output from the alternator is good, 10 to 12 volts on the meter is not.

The PCM regulates the alternator voltage output and, if it has failed, could be the reason for low voltage.



What is the condition of the batteries?

Check the actual voltage at each of the batteries. Good batteries will read between 12 and 13 volts.

Have someone do a load check on them then check connections to the batteries and alternator as well as ground connections. Make sure they are all clean and tight.

After that, if nothing has changed, you will probably have to take it to a shop and have the PCM checked.

 

[Monroefiredog1]

Thanks Howard,



I had the batteries checked twice and both are goo. Thay were installed about a year ago. I suspect that the PCM is bad, just hope it is something else.



Thanks Again