When your checking for voltage at the Battery, what RPM is the truck running at? Most Alternators will not put out maximum regulated voltage till the engine is ran between 1500 - 2000RPM. Any time we do charging system tests on customer vehicles, we have to run the engine at this RPM.
Do you also do any voltage drop tests on the wiring on the feed and ground sides?
When i get back from work tomorrow, ill take a look at one of my electrical diagnosis books for the class i took at college as i know theres some info there on Chrysler external and internal regulated alternators and there sensing circuits. The sensing circut for the truck your working on comes via the ignition switch.