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

Did you check your firewall connector at the fuse block?

Check the alt output terminal with the eng off to see if it is hot (12 volts). Ron

Yep, its hot.

The alt/reg are good and the reg is grounded. That only leaves the blue or the green field wiring and possibly a very poor connection in the circular route from the alt output stud/in to the ammeter/out to the battery (bulkhead). With a jumper wire with alligator clips on each end jump from the alt large batt stud to the male field terminal itself with the blue wire on it & see if it charges now & if not then full field it by taking the green wire off of its' male terminal and ground the male terminal for 3 seconds max & see if it charges. This'll tell you which circuit (blue or green) is open. Unless there's been excessive amperage (not the case here) which burns strands or insulation or frayed wires/bare insulation from rubbing or pinching, wires go bad on the end connections so start there on each end. Have all lights off when you full field as it's hard on them & if you have a 6 or 8 gauge jumper wire handy run it from the alt output stud to the batt positive post for further protection but if you stick to 3 seconds max you should be fine. check voltage drop (the difference) between the alt output stud and the battery positive post once you get it charging & if a problem there start with cleaning the bulkhead

Thanks. Will give it a try.