JW, I assume your AD is 12V?..or going to be.
The 56 above and your AD have ammeters. If either wants an indicator light, you buy a socket and bulb and add it somewhere. There are many nice looking ones on the internet. You need the two wire type. If not, wire to ignition (switched power) as described.
I am not advising on wiring when keeping the ammeter in a 12V and/or alternator conversion. A bulb and a volt meter would be part of the conversion. Abandon the ammeter. Attach all of it's wires together on a suitable terminal block.
Ammeter modifications and wiring for alternator conversions, keeping ammeter, is covered on Stovebolt pages. Do these at your own risk.
