bench test dash cluster guages

Well I've used batteries. The gauges, outside of the amp gauge, operate on about 5 volts. You can take some AA batteries and use them to check deflection. Each battery is 1.5 volts. One battery will give about 1/3 scale on the gauge, 2 will give about 2/3 and three which is 4.5 volts should give close to full scale. But this just checks the integrity of the windings in the gauge. I just tape the batteries in series and run a negative connection to the ground or sender side of the gauge and positive to the input side of the gauage. I just leave them connected long enough to check the deflection.