74 scamp, no turn signals. All other lights work.

Well I'd figure out WHY the "whut ya got" now is AFU first. If the ammeter is stuck then deal with that. But get power back FIRST

Look out in the engine bay at the bulkhead connector and start relay. Identify the fuse links which almost always have a molded "tab" on them for ID. See if you have power at both ends

"Rig" a way to get up to the ammeter. See if you have power on both sides of the ammeter.

Get into the back of the fuse panel. One of the brass busses in there should be hot at all times, the other one hot with key on.

Disconnect the bulkhead connector and examine the terminals, for melt damage, damage, corrosion, looseness, etc.