73 Dart Alternator doesn't show charge anymore.
From your video, it seems everything you checked was working normal other than the alternator circuit.
The battery was powering the ignition which takes very little current, and that's what the ammeter showed.
When the lights were turned on, the ammeter showed more power being drawn from the battery.
The open white circles and squares represent connectors. The 'engine connector' is a common location for problems to develop on the cars that have them.
Look around the right rear of the engine.
From your video, it seems everything you checked was working normal other than the alternator circuit.
The battery was powering the ignition which takes very little current, and that's what the ammeter showed.
When the lights were turned on, the ammeter showed more power being drawn from the battery.
The open white circles and squares represent connectors. The 'engine connector' is a common location for problems to develop on the cars that have them.
Look around the right rear of the engine.