Ammeter waving when ignition is on.

Traxfish said
Well, ran some tests.

Pulled the steering wheel and inspected the switch, switch is fine.

Disconnected both the switch connector and the flasher, Ammeter still did the wave with ignition in both ACC and ON. Found a broken wire on the switch cables after the disconnect. The orange wire to the gear selector light. My wiring was shoddy on that one as I had limited wire and it already had splices in it and moving it around separated the wire in the crimped splice. That isn't the problem, but it is a problem.

The round fender light on drivers side wasn't working. Works on passenger side. Disconnected it to isolate it and the ammeter still did the wave in both ACC and ON. Possibly a short in the line before the bulb?

Tried it with lights on and off, still had the issue. Turning on the lights dipped the ammeter well into the discharge side and still did the wave in both ACC and ON.

I put the charger on the battery. It's currently reading 13v and 1.25a.

Is that an automatic digital charger? If so, let it do its thing.
Still 1.25 amps at 13 Volts is a fairly slow charge. I don't know what that might go up to at 14 Volts, but not 20 amps. A couple years ago I hooked a low battery up to manually controlled charger. At 14 volts the battery was sucking 30 amps. Changed the setting so the battery was seeing 13.3 volts and the battery was sucking about 9 amps.

Lights on - should see about 12 amps discharging, key off.
Lights on with key in access and should see about 14 amps discharge - steady.
The extra amps are going through the points and coil, or ECU and coil, and maybe the alt roter - so don't do this for a long time it will heat the coil.
The ammeter scale is roughly 40 amps discharge to 40 amps charge.

The turn signals are only hot with the key in run or accessory.
The headlights and side markers and brake lights are always hot.