Unplug that connector, you have a bad connection causing a high resistance and causing low voltage high current at that connection and that will make a lot of heat. Run a wire from ammeter to fuseable link and don't use a connector. Then see if the problem goes away.
Ammeter is bypassed as well as having the main power to/from the interior bypassing the bulkhead connector. Tbh, I don’t know if I even have a fusible link. I may have accidentally cut it out when I did the bulkhead bypass