Where is the voltage regulator on a 2000 dodge ram 1500?

Many are now built into the Alternator, if not, follow wiring from alternator.

Disconnect the negative battery cable, remove the alternator, remove the rear alternator cover, and the voltage regulator/brush holder assembly should be staring you in the face. To keep the new brushes retracted during installation, insert an opened paper clip through the hole in the brush holder and brushes. Clean the slip rings with #240 abrasive cloth.