GREAT NEWS....and bad news...

I can't see how the Amp gauge would cause the smoke under the hood and a fuse to blow. The amp gauge is nothing more than an in line shunt with a small meter across it that senses a voltage drop across the shunt.

The amp gauge can fail by the meter going bad but the electrical system will still work. Or the shunt could over heat due to to much current and fail open in which case its the same as opening a switch or a fuse blowing.

What you describe is an indication of to much current flowing through the circuit due to a short to ground, or a high resistance connection in the bulked connector or possibly to much output from the alternator because of a bad regulator or simply a low battery causing the alternator to output its full capacity exceeding the wires rating.