When I added the Voltmeter to mine, I pulled the + connection from fuse #10, which is switched hot. I ran a new ground to the chassis ground screw beside the console, and tapped into the clock light wire for the illumination. It works well, and matches the voltage output that I see at the Battery. Connecting the other gauges is another story entirely. I have Volts, Oil Pressure, Economy, Oil Temperature and small clock (with new capacitors). It's all good.