fusible link smoking

If it's smoking!!!! Unhook the battery!!!!

What did you have powered up?

This is either indicative of a short, a bad connection in the bulkhead connector, or the link failed and is just "finishing up" LOL

Remove the battery ground. Wire a 12V test lamp in series with the ground connection. A glow means a small current. A bright lamp means more.

Make sure the ammeter connections are "safe" and that the alternator charge wire is "safe."