No power.. Ammeter questions.

Because you can tell from the photo. That stud, and the wire ends of the black/ red wires, have been HOT
Which suggests that the resistance was not internal. I disagree the photo shows heat on the red ring terminal and wire. It may be, but I don't see it.

It will likely show continuity with an ohmeter, but you cannot measure a few hundredths of an ohm that will tell the tale.
I agree small resistance will not show on a typical meter. However it will show if the problem is what the initial test appeared to show. That is, his test indicated there is a break in continuity internally. Initial was NO power - therefore a break in continuity.

There is an old thread about converting to a voltmeter.... Brazing/ soldering the studs to the ammeter "guts" will prevent future heating These are a poor design.
Sorry, on these points we'll just have to disagree. I'm with those who view the weakest point of the design as the multiple connections.

I agree with Redfish on all points.
RedFish said
that black wire has a welded splice where it branches to several places. One branch goes to the ignition switch. At switch on it feeds a portion of the fuse box. You lost radio, wipers, signals, that portion of the fuse box, so I suspect you have another problem. Melt down at the amp meter is/was failure at the weak link. It's rarely the root problem. Have a look at a white plastic harness connector under the steering column. These multi wire connectors melt down to cause short/crossed circuits.
I have a good used amp gauge and other parts for you, but to toss it in there and toast it too is not a good plan.
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