Today making a drive to drop off some deer meat to be packaged, my trucks alternator voltage jumped to 18v for a couple of minutes, then went back to normal.  

 

First thing I am going to check is my grounds.

 

If they check out to be clean and good should I put in a external voltage regulator like on the 12 valves? 

no need for an external regulator.  

 

Start with the grounds and go from there.  I would be willing to bet on that anyways.

Actually not a ground issue. Check the green wire from the alternator to the PCM this is a variable ground lead that controls the alternator field voltage. If the green wire makes contact to ground the alternator will run wild.

 

 

Edited November 10, 20177 yr by Mopar1973Man

I had a ground lead pop off the battery 2 winters ago, resulted in voltage gauge spiking to 18. 

Interesting...

Thank you for the help.