Challenger T/A, bone stock, rallye dash. Noticed ammeter discharging while driving. Assumed alternator was kaput, so pulled it and took to local shop. They say a stator is bad, so rebuild and test unit. Test voltage regulator at same time. Both are good.

Install alternator and voltage regulator. Check voltage at battery with engine off, and get 12.65v. Start engine and run high idle. Get 12.4 v at battery terminals. Ammeter showing discharge. As expected, discharge increases with use of turn signal, brake lights, head lights, or radio. Run a jumper from voltage regulator case to ground. No change. Run a jumper from the hot lead on the alternator to the negative battery terminal. Get 12.4v. Pull field lead, and run jumper from terminal to negative batery terminal.
Same 12.4v. Since everything in the dash is working, assume loose connection at the ammeter is not the issue. Pull alternator and take it to local O'Reillys. It tests fine, 14.2v steady, 15.4v high limit. Re-install alternator,and run through everything again with a different voltage regulator. No change.

What am I missing here?

Ken