I don't know the codes, but immediately melting a fuse typically is a dead short. Unhook the sensor and probe the wires for continuity to the negative battery cable with key off. Check each for 12v with black probe on negative battery post. Then turn key on kill switch off (as in will crank if the starter were pushed). Is fuse still good unhooked? Inspection of etv required. Fuse blown? Wiring is bad. What are the resting voltage of battery? Charging voltage? Peak output is around 5500rpm if my memory is correct. Should be around 13.5v at idle. Below 13v.. rectifier/battery. Above 14.5v... voltage regulator/rectifier unit is cooking your battery.