Is there a sure fire way to tell what is going out in my truck? Any manual test that gets the alternator charging aside from pulling it off the have a parts store bench test it?
The gen light is on and the more I drive it the lower the voltage gets. There seems to be no voltage output from the alternator. Battries test ok. I bought a new alternator on the way home tonight but would hate to not be able to bring it back if the problem is really my PCM.

Let me know what you think thanks.

 

take the truck into Autozone and have the charge system checked.
when you say the battery tests ok does that mean you load tested it??
do you have a fluke meter?

 

Has anything been done to the truck lately? I have seen a lot of oil change places, ( and owners ) blow the Alternator fuse when changing the oil! 150A fuse in the fuse panel. Check for power at the back of the alternator with a test light ( the heavy guage wire ) . Have seen a lot of Mopars with over 200000 miles and original alternators and PCMs.

Andy

 

How do you blow a fuse changing oil!!!????

 

I got it tested at both Napa and Parts Plus on the way home and we never got more than 12 volts, I just wasn't sure how to rule out the PCM. No recent major work, it just quit I think.

I took a chance and put the new one in. No gen light and voltage is right where it should be. Lets hope it stays that way.

 

By shorting a metal tool used for breaking the filter loose into the back of the alternator.
At some point in late '90s Dodge realized how easy it was to do and put insulators on the connectors to prevent this.