The mechanical limiter has a bimetal beam that bows when a resistor winding around it heats up. If that winding has failed, beam doesn't bow to open contacts. thus filling the contacts accomplishes nothing.
You don't need to open the gauge. If you'll lift it from the housing you'll find a slither of metal on the back of it that provides a ground path for the limiter. Place a layer or 2 of electric tape over that piece of metal and re install the gauge. That internal limiter is rendered inop.
Mount any aftermarket solid state regulator ( about 30 bucks at ebay ) anywhere you want and route its wires to corresponding contacts at inst' panel.
We could add a little more about the wiring of a solid state regulator and adding a ground wire to the inst' panel but... the above is the jest of it.
