Amps are amps. The ammeter doesn't care about volts. I'm not sure why there would be a voltage reducer off of the ammeter unless it was the line that went to the fuel gauge.

The fuel gauge should have one, and if it doesn't you may have fried it.

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1946 Chevrolet 3600 - "Old Number Seven"

Cavalry's Here. Cavalry's a frightened guy with a rock, but it's here.